[skam1j]

Hi I have a 72 chevelle with a built 496, it has a 4spd muncie and a posi with 373 gears it run strong but i want to be able to cruse at 70 mph with a lower rpm what gear should i change to. THANKS

 

[MEJ1990TM]

3.31's are a real nice in the middle gear. They will work with an M21/M22, but an M20 would be just a hair better. With something making torque like I imagine the 496 will it wouldn't really be worth the effort to swap from a close to a wide ratio though.

 

[skam1j]

Thanks im also getting a vibration at about 65mph shifter shakes do you think the drive shaft needs to be balanced

 

[MEJ1990TM]

That could be the cause, but I'm not familiar enough with drive line vibrations to be of any real assistance.

 

[Euell Florett]

Hi I have a 72 chevelle with a built 496, it has a 4spd muncie and a posi with 373 gears it run strong but i want to be able to cruse at 70 mph with a lower rpm what gear should i change to.

THANKS

GOOGLE "Rear Gear Calculator". Download one for free.

Then, fill in the blanks it asks you to supply.

You get to see what rpm your engine is running with any specific rear gear @ whatever speed you select.

You'll need to know the diameter of your rear tires before you begin.

HTH