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I know a few lucky people, myself included. Never plotted anything, no trick parts, no hop bars, lowered mounts, nothing but stock arms boxed and polyeurathane bushings, a single airbag in RR spring, CE/Summit 3 way shocks, and a OEM rear roll bar. Moroso Trick springs in front and worn out stock springs in the rear. My car was 3650 with me in it at the time and went 1.41 60' with my little 500hp 406 and a 150 shot.
Buddy of mine had a 72, 13:1 468, 200HP Big Shot plate, 3880lbs, full exhaust, etc, same suspension setup. 1.37 60', 9.66 @ 139mph.
All was 20+ years ago, and that was pretty common setup around here at the time. It wasn't perfect or pretty, but it got the job done. Ride height is a factor when it comes to making the stock location stuff work.
View attachment 705345

View attachment 705346

I'd highly buying and reading Dave Morgans book, the Door Slammer Chassis. Lots of good information to be applied.
I will disagree with Billy's statement that pinion angle doesn't affect the hit, as would Dave Morgan and plenty of other racers. It is different for a leaf spring car vs a 4 link or ladder car.

Billy, how fast has you car been with the 632 and chassis mods? What does the rest of your suspension setup look like? How does your suspension plot for IC? What does the front/rear percentage look like?
How can I begin to unravel this^......:oops: I sure hope we can address all of this without this thread turning into a worth-less flame-fest.... I'll give it a try...

First, with all due respect sir, I'm sure you're a great engine builder, and I just want to say that I can appreciate that you're not chiming in here to sell people something, (just as I am not either) and that you just want to help out your fellow drag racers, (as I do). Let me say that there's no point in living in the past.....I mean...air bags you say???? That's why your car in the pic exhibited plenty of roll rotation. Airbags aren't as effective as using a rear anti-roll bar, (NOT an anti-sway bar like your pic shows, because the rear sway bars are much too thin to prevent roll rotation...AKA "body roll" during the launch). With air bags, in many cases in order to get the car to launch without roll rotation, the passenger side bag has to be pumped up enough to cause the car to sit in the staging lanes and on the starting line crooked and all hopped up higher on the passenger side.

Maybe that's all you had back then, but that is no longer the case today, so there's no point in doing that anymore. Especially when rear anti-roll bars are more effective, your car won't sit with the passenger side way up in the air, and even the bolt-in rear anti-roll bars are much more effective than air bags are, and can be had for $400 and all it takes is to drill four holes into the rear frame cross member of the car. Piece of cake. The whole install is easily accomplished within two hours even if it's being done without a lift in your driveway.

"ride height has a lot to do with making the stock suspension work" you say??? That's funny because I also mentioned ride height in post #41 in this thread, and I also explained in detail why that is the case, and exactly how lowering the car changes the instant center length. Did you know that? I guess you missed post #41 here. So perhaps if you read that, you might see that at least in some ways, your viewpoint and mine aren't as far apart as you originally thought.

Furthermore, by pre-loading the coil spring on one side of the car like that, (whether it's done with air bags or via other means)you can often cause a dangerous condition for cars that do long wheel stands, because the pre-loading of the springs differently from one side vs. the other can cause the whole car to pull to one side during the gear shifts. This becomes critical in the situation where the car wheel stands, and the driver needs to stay in the throttle and grab second gear to bring the front end down to earth in a controlled manner, instead of backing off the throttle which would cause lots of damage to the headers, trans pan, and oil pan. If the car pulls to one side during the 1-2 gear shift while the front tires are still off the ground, guess what??? The car can end up on it's door, or even go into a barrel roll down the track if the wheel stand was high enough during the gear shift. I've seen both of those things happen.

If the launch needs to be managed or controlled with the suspension, then it should be done with varied shock settings from one side of the car to the other using double adjustable shocks, instead of pre-loading the coil springs differently from the passenger side vs. the drivers side. Taking care of that with double adjustable shock settings instead, will never cause the car to pull to one side during the 1-2 gear shift, nor during any gear shift. This is important information not only from a technical viewpoint, but also for safety reasons. It sure isn't pretty when a door slammer drag car ends up on it's side.

Second, you say that leaf sprung cars are different than cars with 4 link rear suspension? That's funny because that's exactly the SAME thing that I said. Sounds like you're just looking for an argument. May I suggest that you re-read my post sir?

Third, so you "highly" recommend Dave Morgan's book, eh? Well so do I. So much so that I attended Dave Morgan's 8 hour seminar. And it helped me out so much that I attended it a second time two years later. It's actually amusing that on one hand you call into question and even attempt to debate with me on the points I've made, and then you turn around and "highly" recommend Dave Morgan's book, because it just so happens that most of the things I've shared here in this thread were things that I first learned from Dave Morgan. OOOOOPS!!!!!

In both Dave Morgan's seminar classes that I attended several years ago, one of the attendees who paid an extra $80 to the basic $80 fee, brought his drag car to the class, and Dave had it put on the lift for all of us to stand under and look at during one point of the seminar, and we all discussed with Dave what weak points there were on the car in question, and Dave shared with us and with the owner of the car what could be done for improvement. BTW, for a third $80 Dave also would go to the drag strip with you, and watch your car when it launched, so that he can give you more advice for your car.

In the second Dave Morgan seminar I attended, another racer brought his car, and Dave had it put on the lift and he showed us how to find the true center of gravity. I have had other street/strip cars besides my Chevelle. I'm just not one of the guys who list everything in my post signature. I don't want to turn this thread into a childish mine vs. yours contest. This is supposed to be for peoples' education, not a DI_ _ wagging contest. So I sure hope that we can avoid that, and I also hope that it's not the very thing that you're meaning to turn this whole thread into. I say that because I'm mindful of what Tom the moderator already warned us about in this thread when he made it into a sticky.

BTW, Dave showed us a whole lot more in his seminars than his book gets into. Here's just one very small example: Do you know a very simple method to gauge if any part of your chassis is flexing during a drag strip run down the 1320? Here's a hint: it can be done with a piece of dental floss. Another thing he shared with us at the class/seminar was various brands of drag shocks that he had cut in half to display the internal differences, and how the internals worked and how they would make differences at the track. One of the shocks he had was the AFCO "BNC" drag shock, (Big Nose compression) and we learned how it was different than the rest and what advantage it could offer to the drag racer.

Also lots of drag racers will talk about their best run(s) and what their cars turn. But then when you bring your car to meet them at the track, you often find that their ET's and short times that they previously claimed actually only happen about 2 to 4 times out of every ten runs. If you did things the hard way 20 years ago, and your car ran pretty good in half the runs you made, then I say BRAVO to you sir. But today there is no point in doing things the hard and primitive way. (like using air bags). Because some of those out-dated methods don't work as well. And they often don't result in consistency with a number of drag cars.

You touted Dave Morgan's book, (as do I) but here are two things you're overlooking:

#1. Dave Morgan's book has an entire chapter that stresses the importance of INSTANT CENTER LOCATION of drag cars, and he even displays a chart in that same book which displays various instant center lengths. So what good would any of that be if the reader/end-user doesn't find out where the IC length is on his own drag car and how to change it if/when it's waaaay too far off to be effective??? Sure he can just wing it and try bazillion different things and maybe get lucky after 200 or 300 runs down the 1320. But why go through that if the same can be done in 10, 20, or 30 runs??? I will ask you the same thing I ask the wrong-wheel-drive car drivers at the drag strip: why do it the hard way???

#2. The rear suspension software that I use to find instant center location was developed with the help of none other than DAVE MORGAN himself, and it mentions his name right in the program which can be seen by all of us who use this particular suspension software. OOOOPS!!!! And it also has Dave's recommendations included.
 

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That looks like it came out real nice Rick. Thanks for the pics. How thick are the steel pieces you used for those brackets? .125"? .250"? And did you cut them out with a plasma cutter?
it's 3/16 steel. no plasma cutter, combination of band saw and Bridgeport
 

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Where did you get the spring height adjusters/weight jacks from?
they are from Wolfe Race craft but I think they are out of business. pretty sure TRZ has similar adjusters.
 

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9612804044316148862283

Looks awesome Rick, have you ran the car with the new upper brackets yet? I thought about doing the same thing to my housing.
thank you.

yes I did this in January of 2019. have made a little over 200 passes and did Drag Week '19 with it.
 

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I know a few lucky people, myself included. Never plotted anything, no trick parts, no hop bars, lowered mounts, nothing but stock arms boxed and polyeurathane bushings, a single airbag in RR spring, CE/Summit 3 way shocks, and a OEM rear roll bar. Moroso Trick springs in front and worn out stock springs in the rear. My car was 3650 with me in it at the time and went 1.41 60' with my little 500hp 406 and a 150 shot.
Buddy of mine had a 72, 13:1 468, 200HP Big Shot plate, 3880lbs, full exhaust, etc, same suspension setup. 1.37 60', 9.66 @ 139mph.
All was 20+ years ago, and that was pretty common setup around here at the time. It wasn't perfect or pretty, but it got the job done. Ride height is a factor when it comes to making the stock location stuff work.

I'd highly buying and reading Dave Morgans book, the Door Slammer Chassis. Lots of good information to be applied.
I will disagree with Billy's statement that pinion angle doesn't affect the hit, as would Dave Morgan and plenty of other racers. It is different for a leaf spring car vs a 4 link or ladder car.

Billy, how fast has you car been with the 632 and chassis mods? What does the rest of your suspension setup look like? How does your suspension plot for IC? What does the front/rear percentage look like?

I also never "plotted" my rear suspension.

there are only a few holes and bar angles available. within a few passes you figure out really fast what works and what doesn't. In fact I have 3 lower holes on the rear that work well. top most levels the bar and makes the car wheelie, then the next two provide more and more separation. Up top I have found 1 out of the 4 top holes is most effective for all 3 bottom bar locations.

get the lower bar level, and go from there.

this is with an un plotted rear suspension:

705395


this is a few months before that picture:

 

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I also never "plotted" my rear suspension.

there are only a few holes and bar angles available. within a few passes you figure out really fast what works and what doesn't. In fact I have 3 lower holes on the rear that work well. top most levels the bar and makes the car wheelie, then the next two provide more and more separation. Up top I have found 1 out of the 4 top holes is most effective for all 3 bottom bar locations.

get the lower bar level, and go from there.

this is with an un plotted rear suspension:

View attachment 705395

this is a few months before that picture:

Very Nice Rick. But I don't think you would you say that your car hooks like that merely because you got the pinion angle correct, nor that you accomplished those results from the factory stock mounting locations without using any "fancy mounting brackets" as CP Motorworks has claimed. That was the basis of his disagreement with my post. You also must have been very impressed with Dave Morgan's viewpoints (as I am) since you've claimed in the past that you went to one of his 8 hour seminar's. So I'm pretty sure that you and I can find a whole lot more to agree on than to disagree on.
 

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Seems to work. :D Were you running just no hops before ?
 

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And have you raced the car since you made those changes to the front end? ( I mean since you shortened the front travel to 3")??? I think in many cases it depends on the front/rear weight bias of the car in question. For full weight BB GM A-body cars with stock steel bodies, iron blocks full interiors, etc, they're so nose-heavy that you usually need the extra travel in your front suspension to take full advantage of the "stored energy" in the front coil springs for the added weight transfer during the launch. Now for cars with glass hoods, front bumpers, light weight radiators, removed heater cores, and heater ducts, etc., etc,... it's a whole lot easier to still hook good with only 3" of front suspension travel. But the whole vehicle combination is what matters.

For instance, adding Ladder bars, and back halving the car, along with wheel tubs obviously changes the game.
705398
 

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Not to sound argumentative but I disagree with this stressed importance of optimal instant center. I realize it can "help" but IMO, there are other things more effective in making our Chevelle's quick. My own car ran from 11.50's down to high 9's with a suspension set-up very similar to Pete's. Very simple and no modified IC. Don't dismiss what works just because it's antiquated. It works because it's proven. My current Strange 60 has 4 adjustments on the lower mounts. With only 4, there's no point in arguing where IC should be. I'm going to go to the track, try all 4, and like Rick say's "figure out really fast what works and what doesn't". The results are what they are.

In short, I just don't see the need in having a recipe for an IC location when most cars can't get there anyways and more importantly, other factors will work just as well for the ET. Food for thought-
 

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The "NO-HOP" bars put the upper arms at an angle that is good for most 12 second cars, and some 11 second cars too, but places them at the wrong angle for 9 and 10 second cars, (assuming we're speaking of GM A-body cars such as Chevelles, and with anywhere from a 3,000 lb to 4,000 lb vehicle weight). If the car is still capable of getting into the 9 second neighborhood, then your upper and lower control arm angles required will not be accomplished with No-hop bars anyway, (unless they have brackets with more than one adjustment hole like the Art Morrison ones do).

If you want the car to hook then you can't just be guessing at what angle the arms should be at. You need to plot your rear end out with software to find out exactly where the IC, (ie. instant center) is. There are websites on the internet that let you do that for free. If you want, I can help you out. I have software to do that
The only definite and common thing with almost all GM A-body cars, is that with the factory ride height, and all the factory stock rear suspension components, the IC length is much too long for drag strip starting line traction for any A-body car having more than about 350 or 400 HP under the hood. When you exceed that power level, it becomes increasingly unlikely and difficult to manage the straight line traction with just good rear tires. IN 90% of these cars the way they left the factory, the IC is waaaaay out in front of the car.
Well then you either lucked out, and got your instant center in the right place by accident,( that happens sometimes, but not usually) or you went through some trial and error with testing out the results of various mounting point locations of your rear control arms until you got your I.C. location in the right place and you don't even realize it, or a previous owner had the rear suspension set-up correctly. But either way, I'll bet dollars to doughnuts that if I ran your rear suspension measurements through my software, it would show your instant center location as being ideal, or very close to it.
My response about my suspension setup from 1993 as a 19yo kid, going consistent 1.41 60' in 45F degree weather, and my friends 1.37 60' , with zero suspension plotting, a factory rear roll bar and a $50 airbag with 8lbs in it, $23, 3-setting shocks, $20 in steel to box factory arms, and some ES bushings was in regards to your statements above, and telling the other guy there was no way he went low 1.3s without doing your plotting program.

Very Nice Rick. But I don't think you would you say that your car hooks like that merely because you got the pinion angle correct, nor that you accomplished those results from the factory stock mounting locations without using any "fancy mounting brackets" as CP Motorworks has claimed. That was the basis of his disagreement with my post. You also must have been very impressed with Dave Morgan's viewpoints (as I am) since you've claimed in the past that you went to one of his 8 hour seminar's. So I'm pretty sure that you and I can find a whole lot more to agree on than to disagree on.
The basis of my post was that while the ARB's, DA shocks, weight Jacks, multiple plotted points adjustability and some software is nice and makes for a much improved, controlled launch, it is not mandatory for the majority of street/strip cars the TC members drive on a daily basis. I gave two first hand examples of stock suspension setups with pretty respectable 60' times, with basic parts that can be done on a low budget and some thought and understanding.
But your attempt at mocking me about using an airbag and trying to compare that to an 8 second setup is noted.


And with some of them, the upper and lower arm front mounting location, (at the frame brackets) is such that the arms aren't even pointing to each other, and are parallel, (which puts the IC location out into the next town or to infinity) and there really isn't any intersecting of the lines, or in some cases, the IC is actually BEHIND the axle tubes, and even behind the car since the rear mounting points,(the axle tube brackets) are closer together than the front mounting points are.
This isn't even an issue on A or G body cars with OEM or Ford housings and OEM mounting locations.

Multiple mounting holes are ideal since you can then adjust your upper arm angle to anywhere you need it to be for the instant center length that the car requires. However, I thought he was talking about the height of the mounting ears that are casted into the top of the rear end pumpkin??? If that's what he's speaking of then I don't think they can cast the ears with more than one hole in each side. But if he is talking about brackets on the rear end, then sure, brackets with at least three holes each is ideal
Oh, ok. So they have to add the ears to the housing. But they still would be ears being welded to the pumpkin rather than brackets, I guess. So maybe he would be better off if they can weld brackets on there with multiple mounting holes instead of mounting /welding ears to the it.
3/4" isn't going to be enough. My Strange S60 Dana 60 rear has upper arm mounting ears that are 1.5" taller than my stock GM 12 bolt rear had, and that still isn't enough unless your car is into the 1,000+ HP neighborhood. In that case, that would might be all you would need to generate enough hit on the rear tires given the increased amount of axle torque
Well then you should just reply on the lower arm mounting points to adjust your IC length with. You can just use relocation brackets from UMI Performance, or their lift bars. Both of which come with three different mounting holes for adjustment. Don't worry about the upper arm angle. Just use the factory mounting location for the uppers. No biggie.
Sorry, maybe I'm having a brain fart here, but this piece is to a GM A-body car you say? For the life of me I cannot make heads or tails of that suspension piece. So I cannot figure out what that is. Maybe if you are able to post a pic with a broader view of it that shows more, I would be able to comment.
OK but they won't or can't weld ears on it with more than one mounting hole, right? As far as that pic you showedme of the lower bracket, I'm not that familiar with G-body cars so I don't even have a good grasp on what I'm looking at in the pic you posted. Sorry. I know A-Body cars.

So I know about where the IC location was on that car too. His lower arms were UMI Performance lift bars, and he had them mounted in the very bottom holes, so the lower arms weren't even close to being level with the asphalt like some guys say is "required" to hook a 4 link car good,(NOT true). I understand that you're not telling us that. And that you're merely sharing with us what worked the best in your 8 second latter bar Chevelle. . I'm not in disagreement with Ray here. I'm merely pointing out that there is more than one way to skin a cat...
You seem really confused here about a simple and common rear end setup for A and G body cars. And yet you are able to "know about" where his IC was, but nobody else can possibly use more the 350-400hp on a stock suspension car without plotting it out?
Did you eyball the CG too?
Where does the IC come out when you don't have to worry about the upper arms and change the lowers? Ever tried going fast with a bunch of power and a short and high IC?
The amount of contradicting advice here is impressive.

I haven't any first hand experience with Ladder bars like you do. But I DO know that Ladder bars are known for providing a whole lot of anti-squat which can provide plenty of rear suspension separation, (tire hit).
Obviously you know that if the hit is too short, you get the tire bouncing hard back up into the wheel wells, and the tires go up in smoke about 5 or even 10 feet off the line. And of course just as you pointed out, rear DA shocks can be, and need to be used to calm down, or at least delay that rear tire rebound effect enough until the car gets moving along at a good pace.
Now that you've mentioned it, I guess in a certain sense, us less experienced racers are perhaps somewhat spoiled these days with more advanced/more effective DA shocks for the drag strip, (airbags...that made me chuckle...now that's REAL old school stuff right there).
Besides taking Daves classes, reading his book, and plotting out points in your program, I am wondering what actual experience with making changes to an actual car you are driving and testing these changes that qualifies you to give any advice?

I can assure you that you're NOT running 1.3 second short times merely because you've set the pinion angle correctly. Pinion angle has nothing to do with starting line traction. That's a myth. And for some reason it seems to be a very common myth. Now pinion angle just might indirectly effect the way a leaf spring equipped car hooks. But that definitely does NOT apply to coil sprung cars.
Absolutely. I wasn't implying that having the proper pinion angle isn't important. Sure it is. But it isn't what gives you better traction off the starting line. Having the correct IC location as well as a free moving front suspension, (preferably with at least 5" of upward front suspension travel) is what gets your car to hook. You'll also need to dial in some good shock settings too, and of course taller/lighter front coil springs help out a lot.
For being a student of Dave, you seem to ignore the fact he talks pretty thoroughly on the effects of pinion angle and traction.
I ask what your actual experience is when you state that 5" of travel is preferable, without knowing any other factors?

How can I begin to unravel this^......:oops: I sure hope we can address all of this without this thread turning into a worth-less flame-fest.... I'll give it a try...

First, with all due respect sir, I'm sure you're a great engine builder, and I just want to say that I can appreciate that you're not chiming in here to sell people something, (just as I am not either) and that you just want to help out your fellow drag racers, (as I do). Let me say that there's no point in living in the past.....I mean...air bags you say???? That's why your car in the pic exhibited plenty of roll rotation. Airbags aren't as effective as using a rear anti-roll bar, (NOT an anti-sway bar like your pic shows, because the rear sway bars are much too thin to prevent roll rotation...AKA "body roll" during the launch). With air bags, in many cases in order to get the car to launch without roll rotation, the passenger side bag has to be pumped up enough to cause the car to sit in the staging lanes and on the starting line crooked and all hopped up higher on the passenger side.

Maybe that's all you had back then, but that is no longer the case today, so there's no point in doing that anymore. Especially when rear anti-roll bars are more effective, your car won't sit with the passenger side way up in the air, and even the bolt-in rear anti-roll bars are much more effective than air bags are, and can be had for $400 and all it takes is to drill four holes into the rear frame cross member of the car. Piece of cake. The whole install is easily accomplished within two hours even if it's being done without a lift in your driveway.

"ride height has a lot to do with making the stock suspension work" you say??? That's funny because I also mentioned ride height in post #41 in this thread, and I also explained in detail why that is the case, and exactly how lowering the car changes the instant center length. Did you know that? I guess you missed post #41 here. So perhaps if you read that, you might see that at least in some ways, your viewpoint and mine aren't as far apart as you originally thought.

Furthermore, by pre-loading the coil spring on one side of the car like that, (whether it's done with air bags or via other means)you can often cause a dangerous condition for cars that do long wheel stands, because the pre-loading of the springs differently from one side vs. the other can cause the whole car to pull to one side during the gear shifts. This becomes critical in the situation where the car wheel stands, and the driver needs to stay in the throttle and grab second gear to bring the front end down to earth in a controlled manner, instead of backing off the throttle which would cause lots of damage to the headers, trans pan, and oil pan. If the car pulls to one side during the 1-2 gear shift while the front tires are still off the ground, guess what??? The car can end up on it's door, or even go into a barrel roll down the track if the wheel stand was high enough during the gear shift. I've seen both of those things happen.

If the launch needs to be managed or controlled with the suspension, then it should be done with varied shock settings from one side of the car to the other using double adjustable shocks, instead of pre-loading the coil springs differently from the passenger side vs. the drivers side. Taking care of that with double adjustable shock settings instead, will never cause the car to pull to one side during the 1-2 gear shift, nor during any gear shift. This is important information not only from a technical viewpoint, but also for safety reasons. It sure isn't pretty when a door slammer drag car ends up on it's side.

Second, you say that leaf sprung cars are different than cars with 4 link rear suspension? That's funny because that's exactly the SAME thing that I said. Sounds like you're just looking for an argument. May I suggest that you re-read my post sir?

Third, so you "highly" recommend Dave Morgan's book, eh? Well so do I. So much so that I attended Dave Morgan's 8 hour seminar. And it helped me out so much that I attended it a second time two years later. It's actually amusing that on one hand you call into question and even attempt to debate with me on the points I've made, and then you turn around and "highly" recommend Dave Morgan's book, because it just so happens that most of the things I've shared here in this thread were things that I first learned from Dave Morgan. OOOOOPS!!!!!

In both Dave Morgan's seminar classes that I attended several years ago, one of the attendees who paid an extra $80 to the basic $80 fee, brought his drag car to the class, and Dave had it put on the lift for all of us to stand under and look at during one point of the seminar, and we all discussed with Dave what weak points there were on the car in question, and Dave shared with us and with the owner of the car what could be done for improvement. BTW, for a third $80 Dave also would go to the drag strip with you, and watch your car when it launched, so that he can give you more advice for your car.

In the second Dave Morgan seminar I attended, another racer brought his car, and Dave had it put on the lift and he showed us how to find the true center of gravity. I have had other street/strip cars besides my Chevelle. I'm just not one of the guys who list everything in my post signature. I don't want to turn this thread into a childish mine vs. yours contest. This is supposed to be for peoples' education, not a DI_ _ wagging contest. So I sure hope that we can avoid that, and I also hope that it's not the very thing that you're meaning to turn this whole thread into. I say that because I'm mindful of what Tom the moderator already warned us about in this thread when he made it into a sticky.

BTW, Dave showed us a whole lot more in his seminars than his book gets into. Here's just one very small example: Do you know a very simple method to gauge if any part of your chassis is flexing during a drag strip run down the 1320? Here's a hint: it can be done with a piece of dental floss. Another thing he shared with us at the class/seminar was various brands of drag shocks that he had cut in half to display the internal differences, and how the internals worked and how they would make differences at the track. One of the shocks he had was the AFCO "BNC" drag shock, (Big Nose compression) and we learned how it was different than the rest and what advantage it could offer to the drag racer.

Also lots of drag racers will talk about their best run(s) and what their cars turn. But then when you bring your car to meet them at the track, you often find that their ET's and short times that they previously claimed actually only happen about 2 to 4 times out of every ten runs. If you did things the hard way 20 years ago, and your car ran pretty good in half the runs you made, then I say BRAVO to you sir. But today there is no point in doing things the hard and primitive way. (like using air bags). Because some of those out-dated methods don't work as well. And they often don't result in consistency with a number of drag cars.

You touted Dave Morgan's book, (as do I) but here are two things you're overlooking:

#1. Dave Morgan's book has an entire chapter that stresses the importance of INSTANT CENTER LOCATION of drag cars, and he even displays a chart in that same book which displays various instant center lengths. So what good would any of that be if the reader/end-user doesn't find out where the IC length is on his own drag car and how to change it if/when it's waaaay too far off to be effective??? Sure he can just wing it and try bazillion different things and maybe get lucky after 200 or 300 runs down the 1320. But why go through that if the same can be done in 10, 20, or 30 runs??? I will ask you the same thing I ask the wrong-wheel-drive car drivers at the drag strip: why do it the hard way???

#2. The rear suspension software that I use to find instant center location was developed with the help of none other than DAVE MORGAN himself, and it mentions his name right in the program which can be seen by all of us who use this particular suspension software. OOOOPS!!!! And it also has Dave's recommendations included.
Is this a " Gotcha" response?
Because I can certainly respond to each point, but I've already written way more than it's worth in response.
I see zero mention of Dave Morgan or his book in your posts.
The diagrams in his book are good reference for the details you have skipped over, and would make good visual explanations for members that can't eyeball plotted points by laying under a car.
I noticed you completely skipped anything about corner weights and spring preload, and it's effects.
I see zero mention of IC in relation to CG.
I see zero information or related experience of your personal car, how fast it has gone, what it weighs, what the front/rear bias is, suspension plots, etc. I take it that means you have no data to share from your personal car?

Apparently my response and examples didn't set well with you, and you felt the need to knock "old" tech and attempt to educate me on what and why my car appears as it does in the photo.
I've learned in my relative basic experience that some people will spend dollar after dollar on parts that they don't understand, because they believe it's required to accomplish certain goals.
Meanwhile, the ones that don't know, are out doing it.
 

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My response about my suspension setup from 1993 as a 19yo kid, going consistent 1.41 60' in 45F degree weather, and my friends 1.37 60' , with zero suspension plotting, a factory rear roll bar and a $50 airbag with 8lbs in it, $23, 3-setting shocks, $20 in steel to box factory arms, and some ES bushings was in regards to your statements above, and telling the other guy there was no way he went low 1.3s without doing your plotting program.


The basis of my post was that while the ARB's, DA shocks, weight Jacks, multiple plotted points adjustability and some software is nice and makes for a much improved, controlled launch, it is not mandatory for the majority of street/strip cars the TC members drive on a daily basis. I gave two first hand examples of stock suspension setups with pretty respectable 60' times, with basic parts that can be done on a low budget and some thought and understanding.
But your attempt at mocking me about using an airbag and trying to compare that to an 8 second setup is noted.




This isn't even an issue on A or G body cars with OEM or Ford housings and OEM mounting locations.








You seem really confused here about a simple and common rear end setup for A and G body cars. And yet you are able to "know about" where his IC was, but nobody else can possibly use more the 350-400hp on a stock suspension car without plotting it out?
Did you eyball the CG too?
Where does the IC come out when you don't have to worry about the upper arms and change the lowers? Ever tried going fast with a bunch of power and a short and high IC?
The amount of contradicting advice here is impressive.



Besides taking Daves classes, reading his book, and plotting out points in your program, I am wondering what actual experience with making changes to an actual car you are driving and testing these changes that qualifies you to give any advice?



For being a student of Dave, you seem to ignore the fact he talks pretty thoroughly on the effects of pinion angle and traction.
I ask what your actual experience is when you state that 5" of travel is preferable, without knowing any other factors?



Is this a " Gotcha" response?
Because I can certainly respond to each point, but I've already written way more than it's worth in response.
I see zero mention of Dave Morgan or his book in your posts.
The diagrams in his book are good reference for the details you have skipped over, and would make good visual explanations for members that can't eyeball plotted points by laying under a car.
I noticed you completely skipped anything about corner weights and spring preload, and it's effects.
I see zero mention of IC in relation to CG.
I see zero information or related experience of your personal car, how fast it has gone, what it weighs, what the front/rear bias is, suspension plots, etc. I take it that means you have no data to share from your personal car?

Apparently my response and examples didn't set well with you, and you felt the need to knock "old" tech and attempt to educate me on what and why my car appears as it does in the photo.
I've learned in my relative basic experience that some people will spend dollar after dollar on parts that they don't understand, because they believe it's required to accomplish certain goals.
Meanwhile, the ones that don't know, are out doing it.
Waaaaay too much disinformation as well as misunderstanding for me to even get into here without yet another marathon post that most people won't read anyway. You took some of those quotes out of context. I never claimed to have any knowledge about G-body cars per se. And some of those quotes were concerning aftermarket 9" rear end housings, as well as a posted picture that at first glance I couldn't make out.

The one thing that I will comment on is that Dave Morgan NOwhere in his book that I can remember says anything about pinion angle making any difference in starting line traction in 4 link coil sprung cars, and he sure mentioned nothing about it in either of his two seminars I attended. So if I am wrong about his book, then please make mention of the page(s) where he mentions the importance of pinion angle for 4 link coil sprung cars, since you were the one who first made mention of his book "DoorSlammers". Have you even read his book???? Again, perhaps I missed where he said that. I doubt it since he didn't mention it in his seminars, but maybe I'm wrong. I welcome you to point it out in the book that you highly recommended here.

I can give you examples of cars and runs like you mentioned of your buddy's, but again, I don't see the point in your di_ _ wagging games. Furthermore, I NEVER said that nobody's car will work right nor hook good if they didn't use my IC plotting software. I'm not here to sell anything, and I never charged anyone for that. So you continue to accuse me falsely and take my quotes waaaay out of context.

You cannot defend your original statement that having the correct pinion angle on a 4 link coil sprung car will make it hook. Because that is just plain false.
 

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Not to sound argumentative but I disagree with this stressed importance of optimal instant center. I realize it can "help" but IMO, there are other things more effective in making our Chevelle's quick. My own car ran from 11.50's down to high 9's with a suspension set-up very similar to Pete's. Very simple and no modified IC. Don't dismiss what works just because it's antiquated. It works because it's proven. My current Strange 60 has 4 adjustments on the lower mounts. With only 4, there's no point in arguing where IC should be. I'm going to go to the track, try all 4, and like Rick say's "figure out really fast what works and what doesn't". The results are what they are.

In short, I just don't see the need in having a recipe for an IC location when most cars can't get there anyways and more importantly, other factors will work just as well for the ET. Food for thought-
You went from 11.50's to high 9's with a suspension change? That's huge
 

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You went from 11.50's to high 9's with a suspension change? That's huge
LOL, that would be huge! I meant from 11.50's to high 9's I never changed anything in the suspension and as I built more power, it still worked fine. My engine/trans/converter/rear gears went thru multiple stages of changes/improvements but my suspension remained unchanged. Like Pete- boxed and poly bushings, single RR airbag, CE 3 way shocks, and Moroso Trick springs in front. I did put an ARB in it when it got close to 9's but IMO, that has nothing to do with the instant center as being discussed.
 

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If you want the car to hook then you can't just be guessing at what angle the arms should be at. You need to plot your rear end out with software to find out exactly where the IC, (ie. instant center) is. There are websites on the internet that let you do that for free. If you want, I can help you out. I have software to do that,
1st post above
. Have you even read his book????

I can give you examples of cars and runs like you mentioned of your buddy's, but again, I don't see the point in your di_ _ wagging games. Furthermore, I NEVER said that nobody's car will work right nor hook good if they didn't use my IC plotting software.
So to be clear, you have zero personal experience doing any of this in practice, only theory. Hence, "disinformation". If you see it as an offense to your manhood, I don't know what to tell you. I appreciate you want to help fellow Chevelle owners, but trying to tell me and others what we have done doesn't work is not a good look.

I've owned Dave's book for 26 years now, I could only read a chapter at a time to absorb what he was saying the first time, and often read chapters twice or more to understand what he was detailing.
It's up to the reader to find the information and apply it.
Kinda feels like I'm holding the Lindberger baby for ransom posting these, but apparently I need more proof. No newspaper to prove I took the picture today, sorry.
Also a few of my favorite lines from the book.
705417


705420


705421


Like Rick said, you figure out real quick what works, when you understand what is going on.
Oh, and my customer with a 1967 Camaro street car, pump gas 434, and a Cheater plate has gone 1.33 60' on Cal Tracs, split monos and 275/60 DR Pro's. :)
 

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LOL, that would be huge! I meant from 11.50's to high 9's I never changed anything in the suspension and as I built more power, it still worked fine. My engine/trans/converter/rear gears went thru multiple stages of changes/improvements but my suspension remained unchanged. Like Pete- boxed and poly bushings, single RR airbag, CE 3 way shocks, and Moroso Trick springs in front. I did put an ARB in it when it got close to 9's but IMO, that has nothing to do with the instant center as being discussed.
You have also probably gone the same route then on shocks. They work ok at the 11 second range, but a single adjustable is the next step for the money. The double adjustable is a learning curve. The ARB is a nice deal too, biggest issue is what design tends to depend on if you consider tailpipes important, and are running a stock style tank.
 

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1st post above


So to be clear, you have zero personal experience doing any of this in practice, only theory.
Also a few of my favorite lines from the book.
View attachment 705417

View attachment 705420

View attachment 705421

Like Rick said, you figure out real quick what works, when you understand what is going on.
Oh, and my customer with a 1967 Camaro street car, pump gas 434, and a Cheater plate has gone 1.33 60' on Cal Tracs, split monos and 275/60 DR Pro's. :)
No, my experience is with a Ford which had a type of 3 link derived set-up. But I didn't have to mess around with it a whole lot. I asked if you can show me the page(s) in Dave Morgan's book which specifies that optimal traction depends on the pinion angle being set correctly. But the only thing in what you've posted pictures above of mentions that the "pinion angle was set" and that's it. Nothing there that backs up what you've previously stated at all.

Furthermore you mentioning a customer's results with Cal Tracs in a leaf sprung car such as a Camaro hasn't anything to do with anything that I've previously stated. And BTW, the words of Dave Morgan in the page that you posted here simply backs up what I had previously mentioned in this thread about more powerful cars not needing an instant center that is as short as the the less powerful cars need. So there again the book is saying what I have been saying. And yet you have some big problem with my statements.

I don't question your ability, nor any success of your customers, and quite frankly the success of your customers is of no interest to me. I've met with Dave Morgan personally, and had a couple opportunities to speak with him face to face, one on one, as well as had e-mail exchanges with him too since he gives his seminar students his e-mail. I believe Dave is retired now, and I haven't exchanged any e-mails with him for awhile. I hope he is still with us and is doing well.

I've learned a lot from Dave, and I consider him to be the greatest expert in the topic of drag car chassis and suspension. The real cool thing about Dave's seminars was that we got to stop him at any time during the 8 hours, simply by the raising of our hand to ask him any questions we wanted to, and Dave would answer any questions we put to him. it was fantastic and I took 7 pages of detailed notes. It was a great learning experience for me, and there's nothing negative about that.

I got to see other drag racers who were less experienced than me, and some who were much more experienced than me ask detailed questions of Dave, and heard the answers that Dave had given them. That too was a learning experience because sometimes it's important simply to know the right questions to ask. So if you believe that your experience alone has given you enough knowledge, then so be it. That's entirely your affair. But I don't believe there's anything that I've stated in this thread that goes against what Dave Morgan teaches in his book, nor what Dave taught us in his seminars. And you have yet to show me anything to the contrary. I think the greatest thing about Dave Morgan that I noticed when talking to him in person was that he wasn't afraid to say: "I don't know". It wasn't often that he needed to say that, but once in a while he DID. And as knowledgeable and wise as he is, he was open to hear what others including his students had to say. Very impressive!!

I agree with you on one thing concerning Dave Morgan: His book DOES have a lot to digest, and yes, it's the type of book that you can pick it up again and absorb something more that you failed to absorb the previous times you read it. But this whole approach you hit this thread with such as "where's your Chevelle and what have you run"...and "here's my car, and here are my customers cars" doesn't hold much weight because people often tend to leave out certain details when they share their stories. It's human nature.

I look at it this way....Dave Morgan has helped many drag racers out over the years and his knowledge is vast. But nowhere in his book nor in his seminars, did he stop to sell himself by showing pictures nor videos of his cars that he drove, or owned. In fact in the back inside cover of his book, it gives a description of his experience, and the only actual hands-on experience of his that it mentions, is his participation in road course and circle track. Nothing about Drag cars. And yet the man is a genius and knows much more than you and I put together do about drag car chassis and suspension set-up. Go figure.


Dave shows his students that drag car suspension is about geometry and physics. If you use those two areas of math to set-up your drag car, you're ahead. If you choose not to pay attention to those things, you can still be successful, but you're not using everything that's available to you. It's as simple as that. And all of the "here's what my car can do, and what can your car do?" crap is merely a bunch of pompous self-advertising nonsense. Dave Morgan doesn't get into any of that garbage. In fact, as wise as he is, I found the man to be very humble.
 

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Not to sound argumentative but I disagree with this stressed importance of optimal instant center. I realize it can "help" but IMO, there are other things more effective in making our Chevelle's quick. My own car ran from 11.50's down to high 9's with a suspension set-up very similar to Pete's. Very simple and no modified IC. Don't dismiss what works just because it's antiquated. It works because it's proven. My current Strange 60 has 4 adjustments on the lower mounts. With only 4, there's no point in arguing where IC should be. I'm going to go to the track, try all 4, and like Rick say's "figure out really fast what works and what doesn't". The results are what they are.

In short, I just don't see the need in having a recipe for an IC location when most cars can't get there anyways and more importantly, other factors will work just as well for the ET. Food for thought-
Thanks for sharing your viewpoint. You're obviously perfectly entitled to it as I am to mine. Some guys who don't have a drag strip in their home state, and have to drive 3 hours just to drag race, and get in 2 or 3 test N tune runs before eliminations begin, and then maybe get in another one or two runs during the eliminations before they have to make a 3-5 hour drive back home while fighting the traffic jams sometimes want the advantage of knowing which one of those 3 or four holes might be the best place to start before they make the trek to the drag strip. And that way they can begin to focus on their shock settings and other things.

But here again, even if you don't care about using any software nor caring about IC location, that's all well and good my friend as long as you don't try to tell us that IC means nothing and all you need to do is have the right pinion angle and you're good to go, or that the "stock mounting locations are all you need". I mean you can say that if you want, but I will disagree with that. Just so you know. However that also doesn't mean that you and I are enemies either AFIAC. Because after all we're fellow drag racers even if we've never met, so we do have a common interest. But ofcourse we're all not going to always agree with one another on all the fine points.
 

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Thanks for the pic.... So you've used a bolt with a couple nuts threaded on it in the upper control arms to limit your upward front suspension travel, correct? May I ask what made you decide to do that, and have you found any advantage to that for drag racing? Was the car wheel standing too high? I can see that what you did there might calm the wheel stands down, acting like a limiter.

If I'm correct in that, then at least your car was hooking very well and traction was not a problem. So in a certain sense, that was a good problem to have.
 

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Here's a quote from Dave Morgan's book "DoorSlammers" that I really like:

"Racing is a pursuit of knowledge. The more you know and apply to your doorslammer the greater chance you have of winning each round, breaking fewer parts, and having more fun. Since there is no University of Motorsports, consider this a written course on Doorslammers 101."
 
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