tire and gear selection
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Joined: Apr 2007
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tire and gear selection
Hey guys, i need help with a gear selection. I have a 87 vette with a worked 406. I'm currently run a 3:75 gear with 26" tires through a dana 36. I'm making the up grade to the dana 44, but I would like to run more gear. The 427s is what i perfer, but i'm not for sure if I could make it through the quater mile with that gear and the 26" tires. If anybody could shed some light on this for me it would be great.
Thanks
purplehayes
Thanks
purplehayes
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
It is simple arithmetic. Your 1/4 mile mph won't change much if your engine can rev high enough. Take your current 1/4 mile mph and figure the rpms it takes for that speed with the 4.27 gears. Will your engine turn that high and produce power as it approaches those revs?
RACE ON!!!
RACE ON!!!
Melting Slicks
Joined: Mar 2004
Posts: 2,141
Likes: 2
From: Pittsburgh Pa
well my vette with 3.45's could do 118mph at 7000 rpms in 3rd gear with a 275/40 18 inch tire (i don't trap 118 it was just capable of).. and when i went to the track after swapping 4.10's i had to pass the traps in 4th(shifting into 4th around 100mph) which is a 1:1 ratio if you have an auto it would be 3rd.. in my camaro i had 4.56's and a 700r4 and trapped 110mph in 3rd with 245/50 16's with plenty of rpm to go.. 4.27's would be fine on a 26inch tire as long as you are able to rev the motor some..
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by purplehayes
The motor is making hp up to 6200. The car is coming throung the trap 5700 or so, with the 3:75. I'm also planning on installing a rev kit to aid with the rpms. hoping to raise my rpms up to 6500.
If you are trapping around 118 MPH (5700, 26", and 3.75:1) then the 4.27s will be close at 6500 RPMs.
RACE ON!!!
Melting Slicks
Joined: Mar 2004
Posts: 2,141
Likes: 2
From: Pittsburgh Pa
4.27's in a street car isn't a great idea if you are auto especially if you had a big stall.. i'd stick with the 3.75s till they blew.. then 4.10's at most.. being right on the edge leaves no room for improvement. and also does your converter lock going into 4th that fast? if so and its not of some quality kiss your converter clutch goodbye.
Last edited by pr0zac; Feb 19, 2008 at 09:35 PM.
Drifting
Joined: Jun 2002
Posts: 1,491
Likes: 6
From: Portland Oregon
Here you go: http://www.f-body.org/gears/ quite a few transmission options in the scroll down menu or you can enter your own ratios.
