750HP Have you looked into running a torque proportioning diff? Check Serria racing products out of Washington state. I run one in my Ford 9in. No locking and unlocking. Pulls strong thru the turns. Lot of stock car racers run them on road racing. They can be set up for oval or straight or road course. They handle 700 plus HP and 3400 lbs. with no problem. I use to run a Detroit locker, no contest to what the torque proportioning diff. feels like. No clutchs or springs in it just worm gears. They run about $650.00 US. Good luck................