10 bolt Chevy rears won't handle much of that abuse, I don't know about Pontiac...one of my most memorable "ha, ha" events was doing extended brake torque competitions in a posi 318 'Cuda with a 727 trans, and a friend shattered the rear of his Impala and tore off the cover when he tried
Turbo 400 is pretty darn strong, just make sure your u-joints are in good shape.
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching
