Ordering New Transmission, but What Gears ?

[Run to Rund]

Scott at Jerico talked me into 3.08 first (1.93, 1.34, 1.00) and said it could be changed to about 3.19 later if needed. His argument was that I would have no time in first with 3.19. I have found with the right clutch slippage, I am OK, but still wonder if 3.19 would be better. If I do decide to change, I will discuss gear strengths with Scott.
I also have a torque type engine that I don't want to over-rev and gear the diff for the top end, then take what I can get in terms of first gear.

[Adger Smith]

Aubrey,
I think the 3.19 is too steep a gear for you combination. It will have too much 1-2 drop and with the 5.13 rear gear you have you will never hook it. IF I tried it I would use 4.88's in the rear. I think you have the shift point just about right. You might want to pull it 200 early in low to second with all that new gear ratio. then string it out in 2-3 & 3-4.
One thing about it is all the thinking and planning needs to be verified by testing.
Do Not shove what you want at the car.
Let the car tell you what it wants.

[Troy Henderson]

Lots of good information, give us an update when you do some testing.

[Rich Biebel]

40+ years ago on 7" slicks I learned that the steeper first gear Muncie transmission would only run fast when the traction was very, very good.

Even in a small block hydraulic cam rpm limited 3200lb car.

A 2.5 trans with a 4.88 rear gear and a steel flywheel dug holes in the starting line sometimes......

Basically we needed an aluminum flywheel at the minimum to adjust to the track conditions. Going from a 2.5 to a 2.20 first was a huge change and we threw that at the car in desperation at one race. A bog was faster than a spin........by a lot...We were racing on asphalt then and hot summer was way less traction than cooler conditions by a mile....Smoking the tires on the launch was normal....but only a little....

The fastest car in our class ran less gear in the trans and upped the TQ as much as possible with long collectors and other tricks....

Back in the traction limited days of 7" slicks...

Basically I think you have to pick something that is not as aggressive as you might like or think it could use. A happy medium so to speak.....

I don't miss those days one bit.....LOL

[Adger Smith]

Rich,
I think we walkd in the same shoes. I cut my teeth racing with a 69 Z-28 as a stocker. I raced it while I was in college. We carried 2.52 and 2.70 gear set trannys with us,as well as a 14 lb alum flywheel and a 34 lb Flywheel
I also had an alum hat with a Schiefer alum plate I had a lot of trouble with the heat shield. Back in the day it was fun, but today it would be hard work.

[Rich Biebel]

Yes we did Adger....

My race partner and I became friends with a man that had a '69 Z/28. It was nearly new but was a racecar running F/S at the time. He had fully prepped the car and it had a race engine I drove it a couple times.

I was convinced he should get that 2.20 first gear trans out and I installed a 2.5 first like we ran in our car.

I was used to the hydraulic cammed engine we ran....350/295

His 302 was nothing like the 350 and would spin the tach to the moon if it spun the tires which it did. Leaving at 6500-6800 and with not much traction at our local track.....well forget about it......LOL

I also learned that the 2.5 box would not shift anywhere near as good behind the 302 at the much higher rpm...

Broke some trans parts pretty quickly with it but man that car was great fun to get behind the wheel of....

Black with white panels on the hood and trunk....black and white houndstooth interior and the cold air hood with all the stuff to go with it....except he threw some of it away thinking it was no good for racing....

The car went 12.1's in F/S in 1969 or 1970

[Aubrey N Bruneau]

I'm getting closer to settling on this. Thanks for ALL the "combinations".
Yes, it's more inclined to be a "torque engine", but it still does pull nice up at the big end.