I installed a 81 Chevy 1/2 rear in my 51 Chevy 1/2 6 years ago.Used the 4x4 rear axle so it has the 6 lug pattern to match the front in my case.The axle looks fine ,its only about an inch and a half wider than the stock set up.You have to set up the axle with the correct pinion angle, then weld up the new spring perches.Have a driveshaft made, new U bolts and of course change out the old torque tube transmission to a tranny from a later model GM vehicle. There are a few odds and ends I didn't mention, you'll figue it out.I had never swapped in a axle from a different vehicle before ,but it was no problem at all.
