Hi Tom,
That sounds kind of scary
Torque reaction was the first thing that came to mind, however it would have to be a very serious 302 for that to be the case.Not saying it aint the case though.
Just highly unlikly
Seriously though.............
Firstly i'd be getting out the tapemeasure and checking the rear wheel alignment for anything obviously out of square
Failing that i will need more info on the rear suspension setup?
Take some pics if you can of the rear?
You mentioned a detroit locker, if its the automatic locker like the origional, there a pig to drive with in anycase, and wont help your prob, i'm tipping it caused it in the first place.
The load placed on the drive train by the locker is incredible especially with big rubber.
After saying all that you may as well check the bushes in the locating arms too.
I'll be interested to hear how you went??
Best of luck! Robo