10 or 12 bolt chevy or GM rear end is a good start. mounting kits are available from http://www.chassisengineeringinc.com/chevy/1937-1954chevpu.htm
BUT they have a kit that is about 135.00 for the weld on brackets after you have got the 10-12 bolt r-end. so see chevy duty's
'''Our conversion kit allows you to update your existing axle to any 3-inch diameter rear end. Recommend use of early 1970's Camero or Nova rear end. Welding is required. This kit also contains provisions for modern shock absorber mounting.
Part # 93-311 Price Qty $139.95
''' chassiseng'ring makes this product. this kit just makes it easier to do the swap cause the centering of the original axle is off by 1.5'' ... Do your homework and don't just pick something up that's cheap cause you only want to do this once.
go to gearing and plug in your tire size, rear end ratio and calculate your speed @ a given RPM
It ALL depends on the whole package, tranny, engine, engine torque range, rear ratios and what you need it to do. Mine is a 77 chevy 4x4 burb 3.40 rear end 12 bolt w/ the big 2.75''x11' brakes, 6 lugs. my front is 6 lug 10'' disc. I also have a T5 5 speed. the complete rear end completely rebuilt w/ the 3.40 + kit $7-800. then you have to install it and make a driveshaft...