Advice on powerglide first gear

[casrak7]

2,900 lb race weight. Quarter mile only. grudge race car. 408 LS based engine. Peak power of 729 at 7550, peak torque of 573@ 6200. 6500 converter, shift at 8000-8100, cross around 8200-8300. 4.56 gear, 28 or 29" tire.......whichever seems to cross where we need it to. Expect the car to go very low nines at around 144-145. If we were to run a powerglide trans, what would be your opinion of the ideal first gear on the glide? I know a 1.80 will recover from the gear change better, but would a 1.97 first gear be better for overall performance?

[Greg Hill]

That's one of those deals that you just have to try. Not a lot of rear gear but a short tire, I would think the 1.80 but you will never know until you try them both.

[ATI Performance Products]

Originally Posted by casrak7

2,900 lb race weight. Quarter mile only. grudge race car. 408 LS based engine. Peak power of 729 at 7550, peak torque of 573@ 6200. 6500 converter, shift at 8000-8100, cross around 8200-8300. 4.56 gear, 28 or 29" tire.......whichever seems to cross where we need it to. Expect the car to go very low nines at around 144-145. If we were to run a powerglide trans, what would be your opinion of the ideal first gear on the glide? I know a 1.80 will recover from the gear change better, but would a 1.97 first gear be better for overall performance?

We would suggest the 1.87 low gear as it is a happy medium to what you are looking for and still the stronger gearset for future growth. (never met a guy that got rid of HP in the future...) The higher RPM range will want more gear but the lower torque number will struggle on recovery if the spread is too much on the gear change as you eluded to. The steeper ratio PG gear sets get weaker as they are 16DP. They will hold up, but they also will be the part that breaks first.

[pfordamx]

i know its not what you ask but how would a mcclay metric 200 with a 1.88-1.33-1.00 set work out?