632C2

I recently removed the TH400 clutch setup from my car and went to a torque converter. I decided not to use a trans brake and instead I am foot braking the car. First time out (8/25/2022) I managed a 9.47 at 143.96 while pulling the front tires off the ground about 5” and the engine sputtering through 1st gear. After that race I talked with Will(rklessdriver) about these two issues. He came up with some ideas right away. I shared a few videos with him and he was able to give me shock settings and carb ideas that he thought would help. I went to work making these necessary changes.

On 9/22/2022 at Pacific Raceways the first run off the trailer was a 9.22. At the launch the tires didn't come off the ground and there was no sputtering. The next 5 runs were between 9.15 and 9.18. My best 60 ft was 1.289. I had never felt a car pull this hard in first gear! The next day I emailed Will to report my results and to emphatically thank him for his help. I once again sent him a few videos and after he examined them he gave me more recommendations for shock adjustments to use the next time I go out (next season). We are very fortunate to have someone in our Corvette community like Will that is exceptionally knowledgeable and extremely helpful!!


Here is some background on the car. It's a 1967 Corvette coupe. I am still using my same stock appearing motor that includes a factory Chevrolet Tri-Power intake with (3) two barrel carbs, factory cast iron exhaust manifolds, and a full exhaust with mufflers out the back of the car. It's a 582" naturally aspirated BBC using a Chevy Bow Tie block, 4.600” bore x 4.375” stroke. I have gone through a great deal of work to have the engine compartment appear the same as it did when the car was built in 1967. I went so far as to take a current set of Dart heads and make them look like the original factory cast iron heads. Since I have the car's original 427 I was able to make patterns of the factory heads and went to work with my grinder's on the Darts.

The rear-end setup is a Mike Dyer built Tom's 1480 12-bolt conversion with 3.73 gears. Mike did all the machining to get the 12-bolt in the case as well as setting up the gears, posi, and inner axles (is there anything Mike can't do?). Tom's 3.5” halfshafts, outer axles, frame reinforcement, upper control arms, and safety loops are also being used. I modified a pair of factory trailing arms to allow for 15 x 8 wheels with a 6” backspace. Dave Ogden supplied us with the jewelry-like diff caps and the u-joint caps.

I have been running a clutch turbo 400 transmission in this car since around 2016. For those not familiar with a clutch turbo 400, the torque converter is replaced with a clutch setup. The best times with the clutch turbo 400 were a 9.63 et and a 148.14 mph. The best 60 ft was a 1.585 but all others were in the high 1.6's, 1.7's, and worse. I could never get the car to launch consistently. I either left the line slipping the heck out of the clutch or the tires just spun.

Will was able to get me a set of double adjustable Viking shocks for all 4 corners of the car. He gave me detailed suggestions on where to start settings wise and what to do based on how the car was reacting. Unfortunately my inability to have any kind of consistency when leaving the line didn't allow his suggestions to be properly put to work.

Well I was finally done with the clutch turbo 400 and contacted Neal Chance Racing Converters for some ideas. I talked to Doug and my gosh does he know his stuff! We went through all of the data from the time slips, the Racepak data acquisition, and the DynoJet. He ended up suggesting a 9” bolt-together converter with approximately 6000 rpm stall. Doug made sure to tell me to call him once I got a few runs under my belt to go over the new data. When I told him I have a DynoJet at my house and that I use the crap out of it he told me to expect as much as a 100 rwhp loss vs a manual transmission! I told him I didn't care as long as the car would go quicker and I could get some consistency out of it. I also told him about the time I had the 632 in the car with a Coan PG and lost 100 rwhp. At that time I wasn't racing the car so I removed the PG and went back to a manual trans.

I immediately went to work and took the clutch turbo 400 apart, replaced the forward drum along with it's clutches, replaced the front pump, installed new teflon seals, set up all the clearances, installed a new JW UltraBell, and then installed everything back in the car.

I put the car on the DynoJet and instantly lost approximately 70 rwhp! The car was making around 740 rwhp with the clutch turbo 400 and it dropped to 670 rwhp with the new torque converter combination. Again, I didn't care because I was convinced the car would go quicker.

I am now on a mission to get in the high 8's. I think if I can find another 30 rwhp while keeping the stock appearance and apply Will's shock recommendations I might be able to get there!

texas_c2

Nuts! I love reading about your cars. Thanks for all of the background on the pass.

TAlvarez

Very impressive. Thanks for the detailed write up. Keep us posted on your future accomplishments.

Ted

Dr L-88

Sounds like a bad hot rod. We’d like to see some pics. 👍👍😎

427Hotrod

Congratulations Steve! That thing is amazing...you've got it dialed in well!!!


JIM

Chalie M

Thanks for sharing would love to see some video runs/passes of the car, I ran a 540 pump gas (10:1) engine in a 55 Chevy best times were 10.17 @135mph with a 400 turbo trans & 4.56 rear gears,, I always felt I left a lot on the table with them rear gears & wanted to have the car scaled etc..

I commend what you achieved BIG TIME I know what it takes besides lots of $$$$, its a whole new world of trial & error & experimenting, bench racing with other racers like you have done seemed to pay off big time.

Good Luck
Chalie

Avispa

It was worth a minute or two to dig up a couple of your old threads for a picture of the motor. Wow! It sure does look stock, right down to keeping factory style ignition shielding and exhaust manifolds. The whole package is really impressive. What did you do to the exhaust manifolds and pipes? That's a lot of motor to hook up to stock looking exhaust.

Lotsacubes

I love how you’re laser focused on your dual mission. Looking stock yet wicked fast. I wish you were my neighbor with a dyno in his back yard. Really fun read. Thx…. Fully expect to see that sub 9 slip someday.

vjjack04

632C2,
That is impressive and amazing. Sounds like 8s wiil be there soon. What a milestone accomplishment, to say the least. It would be cool to see pictures and a youtube video!

Also, what are you using for rear tires?

DiabolicalDave

Frickin' awesome!

632C2

Thanks, you are welcome!

Thanks Ted!

Thanks! I will post some shortly.

632C2

Thanks again Jim! I have a lot more work to do.

632C2

Thanks Chalie! I appreciate it!

I have done as much porting on the exhaust manifolds as I feel comfortable doing. I opened the outlet of each manifold to 3" on my mill. From there it transitions from 3" to 3.5" clear back to the transmission crossmember. Next is a 3.5" X-pipe followed by another transition back to 3". The mufflers are also 3".

Thanks! I only have 2 neighbors in my area and they don't seem to mind all of the dyno runs I make. Some days I will make 20 or more runs! I have so many compromises because of my desire to keep things stock appearing. Most people don't understand it - in fact all of my racing friends think I am a little crazy because of how much power I am leaving on the table. Oh well. There is always my son Paul's 632 car!

632C2

Hey thanks! I use Mickey Thompson ET Street Pro's.


Thanks!

632C2

Here are a few pics.

4 Speed Dave

Awesome!!!!!! Screw car shows, drag racing is where its at!!!!!

632C2

Agree with you on the drag racing! Thanks!