If you change rears I would suggest a dana 44. If they are tough enough for a viper or a v 12 jag they ought to be good enough for a street rod. For a 6 lug dana look under a Jeep Gladiator, pull cover to id for posi, you can see clutch pack on posi. You could also look under chevy and gmc but jeep is newer and less popular maybe cheaper. My dana was a gmc housing, scout posi, and jeep gear set. Another thought, if you find the deal of the century on a 5 lug dana maybe you could switch axels or have a machine shop redrill your axels to 6 lug.
