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Preparing for 11 seconds

5K views 38 replies 18 participants last post by  Kirk's67SS 
#1 ·
With my last combo I was running 12.70's at 108 consistently. My 68 is more of a "cruise night" car than dragster, but I do like running the street legals occasionally. With the newer cars getting faster and faster I felt it was time to do something. The car is stock with factory air and a 468 (Edelbrock RPM pack) T400, 2800 Coan convertor and 3.73 geared 12 bolt.

I went to Vrbancic brothers racing in Ontario California and told them I need a new engine hopefully 600+ hp. I told them I would like to run pump gas (with a splash of 110 on race day) and retain my Edelbrock Oval 6045 Heads and Air gap performer intake. I also requested a Hydraulic roller cam.

They said no problem (with some minor head work including larger valves) and we're off to the races. The finished product will be a 10.5 to 1 540. I'm hoping to keep my John Avery 850 dp but we'll see.

So my question is,,, What will the car need to keep me and those around me safe at the track. I already have 275 60 MT drag radials. What axles etc will I need to update to?

Thanks Guys!
 
#2 · (Edited)
The rules change significantly at 11.50. What are you planning to run.

At the minimum anything quicker than 12.0 you will need metal valve stems and an SFI approved harmonic balancer. The balancer may never get checked, but the valve stems likely will.

I’d spend the $10 on a rulebook. Why rely on others to tell you what you what you need when it’s easy to find it in writing yourself.

Here is something else to consider. The people in tech don’t know what your car runs. They will look it over as presented. If a car has modifications such as NOS, slicks, fuel cell, or a super charger they will look for certain things, even then they tend to be in a hurry and need to move through cars quickly. They will often only give the car a thorough inspection if there are red flags. It’s the tower that busts you if you outrun your safety equipment. If you do, expect to see someone who will thoroughly inspect the car. It’s useful to remember, not all tracks operate in the same manner. Small independent tracks want the money, large corporate tracks have deep pockets and are afraid of lawsuits, they will be more strict. It’s best just to follow the rulebook for safety’s sake and so you will never put yourself in the position where you can get sent home.

Steve R
 
#5 ·
I've probably made over a hunderd passes at Autoclub dragway. I've been through tech and they usually ask me what the car runs. I won't really know until next time out. The rules on their web site do not give specifics on what axle upgrades I should be running. This is what I'm searching for. I already have metal valve stems and an SFI approved balancer and flexplate. The tech guy advised me to get a driveshaft loop before but said it wasn't something they would kick me out for. I want to get one now though. Hoping to find something that attaches to the trans mount.

Bare minimum IMO, to run down to 11.50, would be driveshaft loop, which you should already have with the Drag Radials if tech was doing it's job, solid body u-joints if you are still using a shaft and yokes with 1310 series joints in it, aftermarket axles if still using C-clips, or c-clip eliminators with the stock axle shafts.
Anything more will be what the rule book says you need for the time you'll run.

You can access the NHRA Rule Book online for free now, you don't need to pay for it.

https://www.nhra.com/news/2019/2020-nhra-rulebook-now-available-online
you'll need to look at E.T. Handicap Racing Section 4A, and General Regulations Section 21
I'll look into the u joints. When I had the trans rebuilt the guy said I had the good u joints but I don't know what that equates to. Not sure what the c clip eliminators are. I'm guessing this strengthens how the axles attach to the center carrier...?

The lack of some of those items might get you a warning to get them fixed, but won’t get you kicked out, however you didn’t mention several obvious items that will instantly get you sent home. Once you run 11.49 or quicker in a car older than 2008 you will be required to have a 5pt roll bar, 5pt harness and SFI fire jacket.

Steve R
Thanks guys! I appreciate the replys!
 
#3 ·
Bare minimum IMO, to run down to 11.50, would be driveshaft loop, which you should already have with the Drag Radials if tech was doing it's job, solid body u-joints if you are still using a shaft and yokes with 1310 series joints in it, aftermarket axles if still using C-clips, or c-clip eliminators with the stock axle shafts.
Anything more will be what the rule book says you need for the time you'll run.

You can access the NHRA Rule Book online for free now, you don't need to pay for it.

https://www.nhra.com/news/2019/2020-nhra-rulebook-now-available-online
you'll need to look at E.T. Handicap Racing Section 4A, and General Regulations Section 21
 
#4 ·
The lack of some of those items might get you a warning to get them fixed, but won’t get you kicked out, however you didn’t mention several obvious items that will instantly get you sent home. Once you run 11.49 or quicker in a car older than 2008 you will be required to have a 5pt roll bar, 5pt harness and SFI fire jacket.

Steve R
 
#6 ·
c-clip eliminators convert the c-clip axle to a press-on bearing and retainer block so that is its much like a 9" Ford style.....so it the axle breaks anywhere along it's length or the c-clip button breaks off or the axle twists off at the spline the wheel and axle don't exit the car causing considerable damage to the car, anything the car might hit out of control, or you.

Looking at the newest rules, they aren't a requirement until you go 10.99 or quicker, or if you have a spool, mini-spools included.
Old spec used to be 11.99 or 11.49, I don't remember which....so you should be good there, but it is still a safety issue IMO if you have stock GM axles are are trying to hook and launch a 11 second car.

I doubt you'll find a driveshaft loop kit that will just bolt to the trans crossmember, you'll probably have to make that adaption of a commonly available loop yourself....but I'm not totally up on what new stuff might be out there for the A-body, somebody could be doing one now.
I did one years ago for a friend where we just built what looked like a second trans crossmember but with a loop in the center instead of a trans mount. He didn't want anything permanent on the car.

I left out the obvious stuff for general track tech....all lug studs present, studs visible if using aftermarket wheels(open end lug nuts and stud protruding though them), dual carb return springs, 1qt minimum radiator overflow, locking trans dipstick, metal valvestems, no snap-on wheel centercaps or hubcaps, factory seat belt, helmet still in cert spec, rear main electrical shut-off if battery in the trunk, neutral safety switch and there might be something I missed.
 
#7 ·
As far as axle upgrades, I would look a 33spline axles at the least with a 540, the torque can twist 31 spline axles on a engine that CI. as mentioned look into c clip eliminators, you will have to upgrade carrier to run larger axles. I do sometimes over build things but when it comes to twisting or breaking an axle it is better to be safe then wrecked. I would upgrade to 1350 u joints and yokes billet would be best but steel works fine at the power level you are going for. this is just personal preference you can do what you think works best for you, the rule book is a great idea.
 
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#8 ·
I bought one of those drive shaft loops that bolts to the trans mount, but it was too small to fit past the 1350 series trans slip yoke. So I bought and installed this one from UMI Performance, ( comes in red or black). This is nice because instead of having straight mounting arms like all of the generic/universal type loops do, it had the mounting arms at an angle to match the angle of the reinforcement ribs on the GM A-body floor boards, (which is where you want to mount it for strength purposes).

So it isn't too difficult to install one of these. I removed the front seats, had the car up securely on jack stands, matched the mounting holes to the reinforcement ribs of the floor, and made marks, and then drilled four holes, (two on each side). I then bolted it to the floor with grade 8 bolts and nuts, and used wide large diameter fender washers underneath thicker regular size washers underneath the bolt heads and the nuts, to spread the load. Then bolted the two front seats back to the floor. ;)

https://www.umiperformance.com/home/product/1964-1972-gm-body-drive-shaft-safety-loop/
 
#11 ·
I used this driveshaft loop. Works great, and no drilling holes in the body. I also upgraded to a G Force trans crossmember. On my unibody car it was amazing how much that stiffened the chassis.

Solid valve stems, SFI flexplate and balancer, roll bar (to 11.0, 5 point under 11.0), sfi jacket, harness. I would upgrade to moly axles, ARP 1/2" wheel studs, solid spicer ujoints (or have an aluminum driveshaft made with 1350 joints). If you put rear disc brakes on you don't need to put c clip eliminators on. They will ok them for being able to retain the axle if the clip fails. In the diff I would also put ARP bearing cap stud kit and a TA girdle cover.

https://www.ramairrestoration.com/c...drill-driveshaft-loop-turbo-400-vehicles.html

https://www.crossmembers.com/

GM Girdles | TAPerformance.com
 
#12 ·
Yep, that's just like the drive shaft loop I had originally bought, which might be fine for smaller 1310 U-joints, but it wasn't big enough for the 1350 series trans slip yoke I have to pass through. That's why I ended up going with the one from UMI Performance.
 
#18 ·
My factory discs brakes aren't good enough?

You need to do your own research as to what safety equipment is required. Much of what has been suggested is wrong.

I helped out at the local track and often had to check cars for the proper safety equipment when they ran quicker than certain ET’s. I can’t tell you how often the driver would tell me, “my friend who races told me this is what I needed.” It’s up to you to figure out what your car needs and make sure it meets the rules based on the ET or MPH you are running.

Don’t skimp on safety, the only person I’ve ever seen killed was a guy with a tube chassis car that crossed the finish line at 122mph, made a 90 degree turn into the wall when a brake pad disintegrated.

Steve R
With all due respect, I consider this research. :smile2: There's a lot of been there done that people on this forum that know much more than I do. Half the time when I do something I end up doing it twice so I'm in here hoping to avoid that. :D
 
#15 ·
You need to do your own research as to what safety equipment is required. Much of what has been suggested is wrong.

I helped out at the local track and often had to check cars for the proper safety equipment when they ran quicker than certain ET’s. I can’t tell you how often the driver would tell me, “my friend who races told me this is what I needed.” It’s up to you to figure out what your car needs and make sure it meets the rules based on the ET or MPH you are running.

Don’t skimp on safety, the only person I’ve ever seen killed was a guy with a tube chassis car that crossed the finish line at 122mph, made a 90 degree turn into the wall when a brake pad disintegrated.

Steve R
 
#19 · (Edited)
Yes Jerry you have come to the Right Place to get the Advise/Info you need

I raced back in the Early 80s with my 65 GTO with a 70 GTO 400 ci
13:30 ET 90+ MPH in the 1/4 on Street Tires Pro-Trac Bias-Ply 275/60/15

Now go to the Track with a little 468 BBC Roller CAM/Lifters about 550 HP
Street/Hwy Driven and Drive to and Back from the Track
Things I did for Safety etc. ;
1. 1350 U-Joints Front and Back
2. Safety Loop at Front
3. Good Front Disc Brakes / but not to good so they Lock up
I have a SSBC A123 Kit ( 69 Camaro GM Stock SetUp )
4. Good Rear Drum Brakes when I ordered my S60 Rearend from Strange I had them put 11” Drum for H1135 Ford Ends
5. LPW Adjustable Support Cover

Things I did to get the Old Girl to Launch off the Line with No Spinning ;
Front End
1. Removed Sway Bar and Loosen up the Tubular Control Arms / Double Nutted
2. Installed Moroso # 47195 250 lb Trick Springs with a 1” Rubber Spacer under Bottom of Coil Spring
3. Comp Eng 3Way# 2610 Shocks Set at 80/20
Rear End Area
1. New Stock Height Rear Coil Springs Moog # 5385
2. UMI Perf Tubular Rear Frame Braces
3. Comp Eng Rear 3Way # 2720 Shocks Set at 50/50
4. UMI Perf Rear Sway Bar
5. Rear Air Lift 1000 Air Bags # 60744 in the Rear Coils Air in the Passenger Side when needed
6. M/T ET Street S/S # 3454 295/55/15 = 10.6” Tread Width / 12.2” SWW / 27.8” Dia. on a 15 x 10 Wheel
7. New Dynamic 9.5” Race/Street Torque Converter 3,500 to 6,500 Stall

See my Signature for my Times etc.

Here is a Pic of the old Girl performing at the Track for the New Best Time




Oh and Fresh Ram Air to the 950 Holley Pro Systems Carb


 
#22 ·
The U Joints are square at 3 5/8 across on each side (each cross) and the cups measure 1 3/16 in diameter on all sides they have a big cap 1330 one that has 2 sides that are bigger. On the 12 bolt side it is usually a billet yoke (no bearing guard) for the 1350 though they may have come out with some casts one recently. The 1330 and 1310 I think are only 1 1/16 caps or 1 1/8 and maybe like 3.25 inches across with the 1330 being not square in other words one cross is 2.6 inches and the other is like 3.6 inches. I think the 1330 also has the locks inside the U joint like yours.
 
#23 ·
Great Pics of the Exhaust and U-joints

Hard to tell what size they are
but the Rearend one looks not that big !? eg. does not look like a 1350 size to me
are those #s on the Front one ?

The Driveshaft looks newish / what Size Diameter and Thickness of Metal ?
you may need to pull the Drive Shaft out and see if any #s on the U-joints for IDing the Size
and I would check to see if the Trans Yoke on the Front of Drive Shaft is IN far enough or is not IN too far

Note I also add Cutouts to my car's 2.5" Exhaust and when we Uncap them it makes a Big difference in 1/4 Mile ET

 
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#24 ·
Here is a photo of my 1350 yoke unfortunately no seal guard like on the OEM but they may have some out with something by now I did mine in 1995. You will also see the 3.5 inch exhaust fits nicely going over the axle and all the way out the back to the bumper also done around 1995. The 1350s are held in at the end with either the U Joint or the clips.
 

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#26 ·
You need to consider some suspension changes to help your car hook with more horsepower.
Your MPH tells me there is some more ET available right now, so if you can make it work better it "should" be ready more power. It can be a fine line sometimes.
My car years ago went 12:08 @111mph and your at 108mph so I think you should be able to get down under 12:50's probably 12:30's
 
#27 · (Edited)
While we're at the rear end, I just replaced wheel studs on one side, found a loose washer behind the spider, and now am getting backlash/ pattern prefect to handle a measly 605 hp /603 ft lbs from a lil 468 thru a stock 12 bolt.

I used Superior axles years back as they were cut spline's not, rolled. But today go with Moser or Strange. First upgrade I made. Well, I painted a stripe down my stock axles and ran those for a few years and then did the upgrade.

Kept the stock 1310 ujoints in the Denny's HD shaft as I wanted a weak point OTHER THAN the stock 3.31 gear set. So I have to change out ujoints once in a while, which tells me to pop the cover and inspect the diff. NEVER use the grease fitting ones that small, or even 1330, ALWAYS solid.


Be sure to check all your rear suspension bolts for tightness. Check all your rubber for deterioration, and replace if neccessary. Still using simple boxed lower and solid Hotchkiss uppers myself, which seems to work mint. The addition of a rear sway bar ( not Anti-squat) also gives better power distribution to both rear tires. When that was added, I didn't have to keep any psi in the airbag in pass side spring. Oddly, if I take the airbag out, it changes, so I leave it in barely inflated.


SHOCKS? ( i;m still with near 20 yr old KYB which , so far seem adequate) rears are almost more important than fronts.

Front end: lots of launches wil rip the swap bar mounts off, so be careful and unbolt it OR use an extended end link bolt with two nuts on it, and unscrew it 1-1.5" for launching. Had to replace the bolts with bigger ones as many of us have had to do.

Got a helmet? :)


SHORT ANS: from what I can see in the pic, boxed lower/ upper arms and new bushings may be in order, Sway bar is nice addition at same time , with new lower arms, or boxed ones, being able to mount the bar. Pop the diff cover to inspect if you haven't lately. Be ready with a new gasket, and 2 qts of gear lube and a bottle of GM posi addtive. Check for wear, backlash. Again, if using stock axles, spend the $300 and replace them. THen you have to pop the cover, pull the pin, the c-clips and remove the axles. Great time to fully inspect.

( with that HD shaft and joints I HOPE someone has replaced the axles already !!!)
 
#32 ·
I had new gears, axles and eaton posi replaced about 6,000 miles ago (probably 8 years). I'll look at a 33 spline upgrade and if it wasn't done already look at eliminating the c clips. The car has sway bars now. Yes, I have a helmet. I've already raced this car many times.

The car always launches perfect and get's good traction. That's probably going to change with the power increase so I'm half expecting it.
 

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#28 ·
Remember safety is job one. If you break a front u-joint without a loop the driveshaft could jam into the pavement.

Regarding brakes... As you approach and exceed 120 - 125 MPH you'll find the turn arounds come up fast. At 131 I made the second one with stock brakes on a '91 Mustang but it came up quick. (OK guys don't beat me up for using Ford stuff on a Chevy forum. [emoji3])

Chas
 
#29 ·
I think the stock brakes are fine. I had stock rear drums and Wilwood pro street disks on the front. Basically a conversion from drums to disks. Stopped from 151 with no issue. I was running 125 with the car with 4 wheel manual drums.
 
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#30 ·
Ive been 10.80’s in the 120’s on stock disk / drums...no big deal.
 
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#31 ·
Ive been 10.80’️s in the 120’️s on stock disk / drums...no big deal.
In fairness, cold patch slows you down quicker than a well-paved tack lol

Just kidding, I love that track.
 
#37 ·
There is no need to join NHRA. Lots of friends race 30 to 40 times a year and don’t have one. I’ve been a member and you don’t need it unless you are running the Summit series, need a competition license by running in the 9’s or quicker than 135 or want a permanent number. One of the perks of a permanent number is you can use it to set up an account with Summit or Jegs which will get you discounts.

Steve R
 
#38 ·
You will need a sumped tank. I hit the 11s with a mechanical fuel pump. I did have a RCI aluminum fuel cell with dual sumped 3/8" lines to a tee in the fuel pump. This single modification made such a drastic difference in overall speed of the car. Especially with a Quadrajet.. I've come to realize a decent Quadrajet will take you pretty far down the scale. I was using a Cliffs Quadrajet..
 
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