ok i have a 71 with a 10 bolt stock
i have a 12 bolt that i just picked up out of 65 velle
it has new locker 411 gears c clip eliminators
and long wheel studs
i do not drive car hard but would like the lower gears
as i have a 5spd trans , ok so should i sell 12 bolt
use cash to drop in gears and locker in 10 bolt OR.
just drop in 12 bolt and and have new driveshaft
made??

This is the wrong place too Ray. Try posting this in Transmission and Driveline. thats where all the rear end questions and answering happens

keep the 12 bolt, the drive shaft is the same length. your early rear is 1 inch narrower, so you can run a little wider tires. and if you keep the studs you can run mags at the track. jim

Just put the 12 bolt in.