904 slipping

And you have "472hp, 525tq" . If you juice up the power plant you need to toughen up the tranny. (and the rest of the drive train for that matter) My buddy went from a stock 383 to a 500 horse 440 in his 70 Bee. He blew the planetaries out of the stock 72 a few weeks ago. It's beefier now!