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Where are my 11's?

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MadMarv

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Discussion starter · #1 ·
Ok, it's certainly winter in New England, and now it is time for me to put my thinking cap on for how to reach those 11's with my '70 Chevelle. Right now here is how it stands:
All steel, glass, stereo, spare, etc. It's a tub.
Global west front suspension, baer disc brakes all around, 1 1/4" sway bar.
Global west lower rear, hotchkis adjustable upper arms, stock posi 12 bolt w/ 3.31 gears.
Front tires: 17*9.5 billet specialties Wheels w/ BFG Comp TA/KD's p275/45(? on the 45, chevelle is in storage), rear tires (for drag) are 15+8 Wheels with MT ET Streets, 26*10.5.
I have yet to resolve my rear tire issue (I own a set of matching 17*11 wheels with BFG 315/35's for the back, they don't fit, I think.. I haven't gotten a longer wheelstud punched through so I can try and mount them up peroid.. ).
The motor, albeit running rich, and I can't find someone or do myself the appropriate tuning, pulled a 564 hp @5500 and 574 ft-lbs @4800 on the engine dyno.
drivetrain runs through a TH400 with a vigilante 2600ish+ converter, gear vendors overdrive, posi 12 bolt.
Last time I went to the track, conditions were slippery. The treaded honda folks there were bringing water down the track with with.
I did muster a 1.9 sec 60' time, with an ET of 12.4lowsomething, on a 1/4 tank of gas.

Easy Options: (I am going to do some, if not all of these, or parts of these ideas)
I have a few ideas for the car to bring those 11's. First, ditch the koni's for some adjustable hals. Dial them in soft for the track, normal for cruisin (which I do mostly).
Second: Ballast. A full gas tank. Perhaps 150lbs of sand?
Third: Front Sway bar, to get some lift. Some say the car gets to squirrely towards the end without one. I'm not a racecar driver, is this too risky?

Harder Options: I may do some of these.
Switch my 3.31's for a set of richmond 3.90's, even though my rear end guy swears up and down they will make to much noise and dosen't want to insall them, but he will.
Camshaft: Ok.. this is all by memory. Stupid me lost the paperwork. It's a hyd roller, with a 292 duration (I think) and .625 lift (that I am sure of).
It has forged JE pistons, a set of nice, tough rods (expensive), and the stock forged crank, 4 bolt mains. It has Dart 320cc Rectangular, $150 of porting by the engine guy.
Up top it has roller rockers, roller lifters, nice rods, and a crane rocker stud girdle thing.
Something is missing here, and I think it's the head-cam combo picked out here.
Would a cam swap for a solid roller (Aside from the lash adjustments), allow me to retain all the streetability I have, while having some power gains, and be able to take advantage of the higher RPM flowpower of my 320cc heads?, or would it just be a better cam in the RPM range I'm in? I still want my streetability..

There are no real rod shops around massachusetts that I have found, let alone one with competent and good ideas on how to make combos match. What should I do? All I want for now is 11's on those 10.5"'s, .

I'm fishing fer good thoughts here folks.. I'd appreciate anything ya toss at me.

Marv
MarvyG@aol.com

I also notice alot of chevelle's running around in mags with 28*12.5 ET Streets.. anyone know they backspacing they use for their wheels? I may as well order one of those wheel measuring machines from percy's HP, set me back 200, but I already blew 2000, so..

Thanks!
 
#2 ·
I would guess your car is mainly set up to be street driven and canyon carving given the suspension setup?

With a suspension designed for turning corners, you sometimes make compromises in other areas...mainly weight transfer that a drag setup needs to hook.

I also see that while youe engine may have some very high dollar race pieces, they might not have been the best choice for a street bruiser/cruiser (mainly heads).

I don't really think one change is gonna get you in the 11's as it sits (unless it's n2o). As I've learned the hard way, for a car to ET well, it needs a completely matched combination.

The power looks to be there by your dyno #'s, but your chassis isn't optimized to straight line hook...a tough combination to get (corners & straight).

To run 11's with most of you combination as is, I would do the following:

unhook the front sway bar
install some drag shocks out front (adjustable even better)
swap out a lower gear set (3.73 or 4.10)...with OD, that shouldn't be a big problem
a sticky set of slicks/street slicks
fill the fuel tank

I don't think gears set up right should be noisy. Maybe speak with another mechanic and get a second opinion on the gear set-up noise.

I'm sure other will have other ideas, these were the first that came to mind with minimal expense & changes. A low 12/high 11 second car should be able to 60' in the low 1.7 range if traction is there.

------------------
Todd Geisler
79 Malibu
11.16@125.8mph
Malibu Muscle
http://www.MalibuMuscle.cjb.net
 
#3 ·
OK,now I'm probably going to get a couple of people who don't agree about my suggestions,but here we go.

Your cams advertised duration figure of 292 means that it probably has about 244 at .050.It sacrifices too much torque in the range that you need it the most.A better choice would have been an advertised figure with 280-284 and a .050 duration of 230-238.

The Hydraulic Roller was also not a wise choice.Why?The BB Chev has an extremely heavy valvetrain which prevents it from revving freely.Now the Hydraulic Roller cams lifters are even heavier than a hydraulic lifter.A better choice might have been a new generation hi lift solid lifter setup.But hey,if you want to adjust the valves why not just get a Solid Roller?
Image


Also your choice of gears is not quite right.Thet don't allow enough torque multiplication out of the hole.They also allow your motor to dip to low in the power curve when you shift gears.This means that every time you shift gears the motor has a delay before it gets back on the cams torque curve.3.73-4.10 would be a good choice.As far as the noise is concerned,you shouldn't have any.Unless the installer doesn't know what he is doing,or you use a straight cut set for racing.

Your converter stall is also too small.When you launch you want your motor to be close to peak torque for an optimum launch.On the street you need to be able to move the vehicle without being on the converter all the time.So a compromise must be made here.A stall speed in the range of 3200-3500 would be good.

I feel that there is at least two more things wrong with your combination.You hit on one of them when you said that your heads had higher RPM capabilities.But I'll let someone else explain it to you.

[This message has been edited by Racer X (edited 01-01-2001).]
 
#4 ·
What was your mph on your 12.4x pass?

Your car has 11's written all over it! You are only missing ONE thing; suspension. Remove the front sway bar, install an airbag in the right rear spring inflated to about 10 psi, and change the rear suspension to move your instant center back (see www.dickmillerracing.com or www.metco-inc.com).
 
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#5 ·
Good question from Bomber, what was your MPH? According to my little ET/MPH calculator, the HP you listed from your motor in a 3900 pound Chevelle will give you an 11.95 @114MPH.

------------------
My 70 Chevelle
 
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Discussion starter · #6 ·
MPH was 108.45, for the 12.4lowsomething run, on the MT ET Streets w/ a quarter tank of gas. MPH last year was 113.7 on a set of BFG comp t/a P245/55 R 15's, but with a 2.275 60' and a 12.703 1/4.
Track conditions were alot better the day I drove up on my radials.
My car is a street car, I try to drive it every sunny day when there isn't something wrong with it. I just want to pull an 11 second time slip, I know it's in there, on the highway a 3-2 floor it kickdown, then back into 3rd has dusted anything I've yet to meet that actually drives on the highway.
I'm probably gonna dump the 3.90's in, he's a good rear end guy, he just says richmond gears are noisy. But I have so many other noises, I think I am just gonna have them put in regardless.
I don't want to have the stall speed re-adjusted, dosen't that spill streetability into the toilet? I get one free stall speed adjust on my converter within the next year and half, little less.

Thanks!
 
#7 ·
If you had 113.7 MPH already, you are very close to a high 11 second run. You will get that timeslip that you so desire.

Jim R.


------------------
My 70 Chevelle
 
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#10 ·
114 mph is good for an 11 with a decent launch. I think you have a lot of cylinder head there (as I am sure will hear about from Racer 1320
Image
) The engine combo is ok but to match those heads you really should have some more camshaft and some more rear gear....with the overdrive unit you could run 4.11s really easily and still be ok on the highway.

You have a couple things working against you...its a HEAVY car...with a heavy car you either need a lot of low end grunt which those heads and a mild converter wont give you OR you need a lot of gear to help you get that land yacht rolling....with the overdrive unit the first thing I would do is a set of 4.11s and then maybe a little stouter solid lifter cam and then just tune it and work the suspension out....you'll be amazed what a nice 1.4 or 1.5 60' time could do for your et.

I race at NED too and I'd like to meet up with you this spring....hopefully I will have my rat conversion done to my 65 by spring but only time will tell. Talk to you later and keep us posted

------------------
Bill
65 SS
Team Member 1013
 
#11 ·
3 things should get you there.1st unhook the front sway bar 2nd lose the 3:31s 4:11s with the overdrive will work just fine and if they're set up right they won't be noisy.3rd you need a little more converter around 3000 stall if the car went 12:40s and your 60ft. was 1:90 the car is not leaving for crap
Image
i was running 11:70s in a 70 chevelle 433cubes 392 casting g.m. heads 163 casting intake comp cams solid 580i 605e lift 246i 256e dur. on 108 l.c. turbo 350 4:11 gears 28in. tall m/t street e.t.s np front sway bar and stock springs 50/50 shocks on the rear and cheapy auto zone shocks out front and i was'nt realy crazy about it but a b&m holeshot 3000 converter you could probably do better with a coan or a j&w or even a tci converter.
 
#12 ·
<BLOCKQUOTE>quote:</font><HR>Originally posted by Racer X:
OK,now I'm probably going to get a couple of people who don't agree about my suggestions,but here we go.

Your cams advertised duration figure of 292 means that it probably has about 244 at .050.It sacrifices too much torque in the range that you need it the most.A better choice would have been an advertised figure with 280-284 and a .050 duration of 230-238.

<HR></BLOCKQUOTE>

I'll have to agree with RacerX here, it sounds like a mismatch of parts. Here's a link to a similar situation, a 4000# car with 3.55 gears running 11.50's thru the muffs all day. Check out the lack of big-name parts and the attention to detail. Note the front swaybar in the pic at the bottom.
http://www.boyleworks.com/ta400/psp/rebuild455jh00.html
 
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#13 ·
What compression are you running. I was going to go with the Dart 320's and I was told the motor would be a dog if I didn't run a higher compression Ratio like at least 13 to 1. I had a few people tell me this and motor is 12 to 1 with a 685/692 Solid roller cam in it.

1970 SS396 aka LS-7 468/TH400
 
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Discussion starter · #14 ·
The engines compression is 9.6:1. Since I already have a set of new richmond 3.90's in the garage, I think I will do those and a set of HAL 12 way adjustable shocks. If that isn't enough, then I guess the next step is one of those new mean solid roller cams.
If you want an idea of how my drag run looks, I take off slow.. like I'm barley moving. Slower cars often pull ahead. Then about 3/4 of the way down the track you hear and see a 4000lb tank ripping up the asphalt, right by most people in the other lane.
Heck, a mustang that pulled a 13.5 1/4 mile was ahead of me for 1/2 the track once.
Peak torque is @ 4800 RPM, which is pretty high I guess.. but with them new gears and shocks to help move the load around some, I am hoping 11's.
Are the 12-Hals nice? I already have those koni red "adjustable" (it says they are, but yeah right IMHO), which are nice shocks, or should I just go right for a nice solid roller cam? I may as well do both, hehe.
My ultimate idea for this car over the next 3-5 years is a accel DFI or whatever they have out that is the nicest when I do it, and an intercooled procharger, all tuned to slap out about 950 horses.
 
#15 ·
Marv, I know I said this all before to you. Gears. a mill like yours needs gear to run well, which is why your 1/2 track speeds are "slow".

Secondly, 9.6:1 is too low for alum heads IMO, but lets not nit pick the mill right now. Its in there and thats that.

I only hope 3.90s are enough. With that OD unit I'd go more. 4.30 or at least US Strange 4.10s for your 3 series carrier.
 
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Discussion starter · #17 ·
Yeah, my rear end guy said US gears ringsets generally were quiet. I figure I already had a set of 3.90's, and I wasn't going to buy a 3.73s by someone else, being less gear. But US gear 4.10's will go right into my 3 series carrier? I would probably go for them if they did, plus they get the thumbs up from the guy I go to for this sort of stuff (he also cut the floorpan and redid my pinion angle with the overdrive).
I need to iron out my tire situation, the only reason I hesitate to put a 4.10 in is because I drive around on 24" tall tires, and they look rediculous, and give me bad rev's.
My car is like a road-racer/straight line streeter combo gone wrong, hehe. When I get it all set up with the ride height junk straightened out (the front end of the car is around 3-4 inches too high), I wonder if there is a place I can play around in and then pay some guy to get stats on my car.. like 0-60, skidpad, 0-150-0, etc.. pinch it up against cars like they do in car and driver and such.

Thanks for the info on the 4.10's.. didn't know you could do that. Heh I am gonna scare myself even more when I drive that thing with a set of 4.10's hanging out back.

Marv
 
#18 ·
Marv

I ran 11.90's with a much smaller cam than what you have now. I think your best bet is more gear and more converter.
My first time out I was running 12.30's and the only thing I changed was a trans rebuild and larger converter,Went from 2500 to 3500 and dropped 4 tenths to 11.90's. And traction helps also. If you get your 60ft down it will e.t. better. I've heard 1 tenth in 60ft is worth 2 tenths in the quarter. That holds true so far in my experiecne. I was hitting 1.8 on the 12.30 runs and 1.6 on the 11.90 runs. So I dropped 2 tenths in 60ft and gained 4 tenths in the quarter.
This last time out I was letting off at the 1000ft cone to keep it out of the 11's due to no roll bar and I was still hitting 12.14 and 12.28. I think I may have hit 11.80's but it was a points race so I couldnt go all out, just trying to be consistent.

------------------
71 Chevelle 454 best 11.92 @ 110mph 1.66 60ft
65 Elco 4x4
68 Firebird 400 4spd. Conv.
 
#19 ·
Marv, with 24" you might get away with 3.73's. I would do the 3.90s, but I;ve heard the same thing. The local "assman" says the same. Its not an issue of strength but of noise.

My car is so damn loud it dont matter.

So, I'll say again, if you decide NOT to use the Richmond set, let me know. They're 165 new. And I'll be buying a set this summer. Yours or new.
 
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#20 ·
Maybe the richmond gears used to make noise, but they don't anymore. I just installed a set of 3.73's last fall and I love 'em. No noise whatsoever. I bought a pinion depth indicator and installed them myself. I think it's in the setup. If you set them up according to specs they're fine.
 
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