I bought a '73 Chevelle wagon for $10 and used the 3.08 rear from it.
By time I paid for spring pads and having them welded in place, had the drums turned and replaced the various brake parts, and bought 5-lug wheels, I think I spent $6-700 on the project.
Mine is a '55 1st so it was already open drive and I'm still using the original SM 420. Its been three years and I've been almost 100% happy with the swap.
I say almost because it sure doesn't pull a loaded trailer with the same finesse it once did.
