couple R-154 swap questions

Is this a common problem? I used to race at the speedway in Vegas and I knew a guy making 850 hp 784 ft. lbs. in a supra,he would dump the clutch at 3800 rpm off the line.He said it was a stock trans.
really??? But a different clutch which can be my next problem. There is only a cheap conversion plate available.... no performance plate....