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Supporting Member
Supporting Member
I need advise or direction to a calculator to determine a ball park gear ratio for the T.
It has 32 in tall tires, a 1 to 1 high gear. The speedo seems about half right and I do not have a tach yet. The rear axle is a chebby S-10, I think, probably a high 2 or 3.00 ratio. I know there are a lot of unknowns and I will pull the cover to find the ratio, but with the tall tires I can cruise the 2 lanes in second and the engine is loafing. I do this for a little more pep. I am not into high speed, but would not want to cripple myself on the highways. I was thinking high 3's or 4.10. The tire heighth will stay. The T needs them for proper stance and appearance.
I have 30" tall back tires and a 3.73 gear in an S10 blazer axle (7.5") and C-4 tranny (no overdrive) and it does well. With an even taller tire, a 3.73 should be near perfect for the street. You can find them in stock axles from S-10's with 4cylinder sticks.
Perhaps this will help. It is from the Tech Pages of the NTBA.

Use this chart to calculate your final drive.​
In order for your calculations to be correct, it is imparative that your
speedometer be accurate. If you know your axle ratio and your tire
diameter, you can check your speedometer.
Submitted by: Michael (Mikester) Light
In two post, I've got everything I need to make the right choice. I can find the 3.73 at the salvage yard for a good price and the chart shows me what to expect in rpm.


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