check this link, very helpfull for axle Swaps
http://www.quickperformance.com/Technical%20Info/sus_measure.htm 47-55 chevy truck flange to flange measurments 60-62" a good swap would be 68-72 nova (i just bought a 68 nova rearend of craigslist for $70)
other good donars include 76-80 camaro/firebird. 68-95 vette
s10, and g-body cars will work with offset wheels being that their 2" shorter then the stock rearend.
hope this helps, im no shop shark but been doing alot of research, since im doing the same for my 49 3600. good luck!!!
