3.73 --or--4.56

i can not decide on if i should use 3.73 or 4.56 gears, motor is a flat top 429..i am using stock car rods ..solid roller cam, 2500-6800 , ported big vale doves and a blue thunder intake, tires on my car are 31-10.5w ,

Is this a drag only car?

Curt wrote:Is this a drag only car?

yes drag only car, we run mostly 1/4 mile and some 1/8 mile races , i dont plan on shifting high rpm, will have to test to see where car like to be shifted at , probably around 5500 range

the shift point isn't as much as a target as the finish line rpm. My goal is to shift at 200 rpm over peak HP. But with the factory rods, you should get the highest gear available to cross the finish line at the desired RPM.



But for sure if you have the two gears mentioned, the 4:56 will be your best choice.

What transmission?

lghting94 wrote:What transmission?

c6

leaning toward 4.56, which is a tad high , but im thinking it will be ok, since i have 31 inch tall tires

Actually it wont be. You will be very close to 5500 at the stripe unless you're making a ton of HP on that almost stock motor. Transmission won't make any difference except on the line, you'll be at 1 to 1 at the big end.

Curt wrote:Actually it wont be. You will be very close to 5500 at the stripe unless you're making a ton of HP on that almost stock motor. Transmission won't make any difference except on the line, you'll be at 1 to 1 at the big end.

5500 with what gear? wallace rpm calultor says with a
4.56 gear
6500 RPM 131.46 MPH
6000 RPM 121.35 MPH
5500 RPM 111.24 MPH

3.73 gear
5500 RPM 135.99 MPH
5000 RPM 123.63 MPH
4500 RPM 111.26 MPH

richter69 wrote:weight of car and converter?

converter is a b-m 2500---unsure of car weight...with a bbc and a glide it was 2790

richter69 wrote:tight converter I'd go with the 4.57.

ok..will do

richter69 wrote:good choice, with the tight converter and short stroke, tall tire...........it would be a serious turd in the 60' dept with the 3.73.

going to run this motor and build a bigger motor over the next year... r u coming up to the labor day race in Tulsa...