75'-79' nova rears work well. s10 4x4 rearends work well also, 2wd ones are too narrow. check out www.chevytalk.com tons of info there.
Im using a 76 Nova rear on a Chassis Engineering spring kit. The rearend must be a factory multi-ieaf job. It bolted up nicely. Using 2 inch blocks, 5 inch factory wheels, 205 75 15 tires. works ok.
I put a 79 camaro rear in my '50 sedan delivery. It was a bolt in. Only had to drill a new hole for the spring bolt so the rear would be centered in the wheel well.
My coupe has a '57 chev. rear in it, was there when I found her back in '85, its a 3.55 positraction, only thing i need to do( but I've been driving it since 85 like this) is center the axle in the wheel opening, as they just bolted her in and didnt take into account the original rear mounts are well rearward, due to the torque tube pivot. as has been stated, Chassis Engineerings kit fixes this perfectly, i bought it, just need to do it...