What gear??

[nova2206]

I have a 3550 lb 67 Chevelle with a 477 iron headed big block with a 400th tranny. It currently has a 1/4 mile set up with a 4.10 gear, tire are 12.50s, it runs damn good in the 1/8th at 6.26 or 6.27 in the heat with a 1.38 60 ft.. I never race a 1/4 mile so what is the right 1/8th mile gear.. I go into high gear about 2 car lengths from finish line.

[us7race]

It depends on how hard you want to turn it but I think more gear will definately help. How tall are the tires? At least a 4.56 if not a 4.88.

[zipper06]

us7race is dead on, if you are turning about 6200 in the 1/8 mi. lites, useing this calculator, and you want to turn 7,000 rpm. It comes out to 4.63 gears. BUT, there could be a hooking problem with the b/blk. We run 5.29 gears with a s/blk and run 5.90@118 and 10.5W tires but it doesn't have the torque of a b/blk.Here is the caculator that will help you decide.

http://www.wallaceracing.com/gearcalc.php

Zip.

[sds10racer]

hey zip, does that calculator take into account diff. shift points?

[Tod74]

I have a 3550 lb 67 Chevelle with a 477 iron headed big block with a 400th tranny. It currently has a 1/4 mile set up with a 4.10 gear, tire are 12.50s, it runs damn good in the 1/8th at 6.26 or 6.27 in the heat with a 1.38 60 ft.. I never race a 1/4 mile so what is the right 1/8th mile gear.. I go into high gear about 2 car lengths from finish line.

That's moving for a car that heavy with only a 4.10 gear.

[zipper06]

hey zip, does that calculator take into account diff. shift points?

No it doesn't, but if you go the site and click on index it shows a lot of different calculations.
I was assuming he's running about 6200 RPM in the 1/8 mi, since he said 2 car lgs. before the finish line he shifts to 3rd gear and 6.26/6.27 ET equals about 108 MPH.

JMO

Zip.

[dparker]

It may not help much to go to a lower gear, for the simple reason that right now your total gear ratio in low is 11.28 to 1. Your total gear ratio in low gear, if you were running a powerglide and a 4.88 in your rearend, would be a 8.59 to 1. If you went to a 4.56 rearend gear your total ratio in first gear would be only be 12.52 to 1. This is one advantage to running a turbo 400 over a powerglide, especially in a heavy car.
Going lower on your rearend gear will pick you up a little but you'll have to decide if it justifies the means, or expense. Just the few things to think about before you spend the moneys to upgrade your rearend.


I have a 3550 lb 67 Chevelle with a 477 iron headed big block with a 400th tranny. It currently has a 1/4 mile set up with a 4.10 gear, tire are 12.50s, it runs damn good in the 1/8th at 6.26 or 6.27 in the heat with a 1.38 60 ft.. I never race a 1/4 mile so what is the right 1/8th mile gear.. I go into high gear about 2 car lengths from finish line.

[nova2206]

Thanks for all the great ideas, my reason for asking is because a good friend of mine had a set of 5.13 for a Dana laying around and I wanted to try them, went ahead and put them in today and I'm gonna try them this Sat, I'll get back on and let you know what happens. I have another buddy with a 3400lb car that runs close to the same set up with a 5.38 gear and he runs 6.0's so we'll see.
Again thanks for the help