What donor axle for my 64?

[Captainfab]

Those are some really tall gears....you must be after either top speed or mpg. The tallest gears I know of in a truck rear are 2.73's, and those were in the mid to late 80's. The truck rear ends from '71-'87 will work for you, but they are 1.5" (~63.5") wider than the one you have now. I think the spring perches will need to be moved also.

[GMCMG]

Originally Posted by Captainfab

Those are some really tall gears....you must be after either top speed or mpg. The tallest gears I know of in a truck rear are 2.73's, and those were in the mid to late 80's. The truck rear ends from '71-'87 will work for you, but they are 1.5" (~63.5") wider than the one you have now. I think the spring perches will need to be moved also.

I'm after MPG. Dropping a 6.2 Diesel out of an 84 in, and a 27% overdrive manual tranny. Hoping to have enough torque to handle gears that tall. That's why I was wondering about a car leaf spring axle, but I haven't been able to find decent information online about dimensions. I know the 79 Trans Ams had a 2.41, but don't know whether or not the dimensions are right.