1970 Chevrolet Malibu Classic - Gear ratio help

My chevelle has a 373 gear in the rear end , I run about 3000 rom at 70 miles per hour , would like to get it down to about 2200 rpm at 70 mpm what gear ratio would that be ?

Calculate RPM for Given Speed(MPH), Rear Gear Ratio, and Trans Gear Ratio (purperformance.com)

(2200/3000) * 3.73 === 2.74


I believe its 2.73 for a chevy


Anybody guessing OP is an auto shop class student? … lol …


Classic cars like this are generally out of reach for teenagers. Since it has been modified for the drag strip, it is probably not a low-dollar clunker.

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If the car is equipped with a 2-speed Powerglide automatic or even a 3 speed Hydramatic, a 2.73 is going to make it dog slow off the line.

You could put a 200R4 or a 700R4 4 speed automatic with overdrive in it. Or if it is a 3 or 4 speed manual, a 5 speed Tremec TKX.

Where do you see that?

I changed a rear axle in a 70s Camaro from a 3:42 to a 2:56 and it brought the RPMs down to that range.