gear ratios

[Ewing M.]

I have a M22 (2.20:1 first gear) and 3.31 rear axle. I want to change rear ratio to equate to 2.54:1 first gear transsmission ratio and a 4.11 rear ratio. What rear ratio do I need to go to? Is it a mathmatical equation to find the answer?

[Patrick B.]

Re: gear ratios

yes, the mathmatical equation is:

rear end ratio = (2.54 X 4.11)/ 2.20 = 4.75

Even a 4.56 ratio isn't as steep as you want to go but it is close.

[Gary R.]

Re: gear ratios

One thought here, if you're indeed speaking of a 63-79 vette differential, the available ratios are 273, 308,336,355,370,373,390,411,433,& 456. Most will fit a 3 series case which should be what you have, a 331 ratio was never a vette gear. If you go to a 4 series gear, other then the US Gear brand, you will need a 4 series case.

[Duke W.]

Re: gear ratios

I have a M22 (2.20:1 first gear) and 3.31 rear axle. I want to change rear ratio to equate to 2.54:1 first gear transsmission ratio and a 4.11 rear ratio. What rear ratio do I need to go to? Is it a mathmatical equation to find the answer?

Yes, but it's quite complicated.

2.54 x 4.11 = 10.44

10.44/2.20 = 4.74

Available gearsets should include 4.56 and 4.88

Unless you have an engine with a very high overlap cam and are doing some serious drag racing, a WR trans with either of the above axles is way too short for normal street and highway driving.

Duke

[Steven B.]

Re: gear ratios

One option to move toward the 4's is to get a lower profile tire, but one too short may look "different".