I had a 70's Vette that I used to drag race in a street legal class with the IRS. I beefed everything up and rebuilt the rear diff myself. I removed the springs in the Eaton limited slip and shimmed it tight so while it still operated as a differential it spun both tires when it broke traction at any speed. I had 500+ hp/torque going though that diff onto pretty sticky tires. I would do burn outs in 2nd gear to warm up the rear tires in the staging area. Had to feather the throttle for the first couple of gears to keep traction. Did this literally a couple hundred times. Never once had a rear diff clutch pack problem. The car was a (fast) pussy cat on the street too.