[Joe Z]

I believe you can lift the rear-end on stands, then with the car in gear(no parking brake) try turning one wheel backward. If the other wheel turns in the opposite dirction(forward) you don't have a locker. Another way is to put one tire on a slick surface, and the other on a good hard surface, and see if all power is lost to the spinning wheel.

By the way, which frame does this car have? Does the engine have alum. heads and roller cam?

Thanks,

Joe