What Can Cause Uneven Tire Wear 8 3/4 posi ?

I just measured the tread depth on my 8 1/4 open rear end (2.93) tires and in my case the passenger side has less tread left than the driver's side.

As a young adult driving a hand-me-down 1969 Chevy pick-up truck (350 auto/open differential) I used to wear the rear passenger side tire smooth because going around right corners it would slip/spin because I pressed on the accelerator too soon (on purpose-Dad paid for the tires).