Optimal Race Trasmission Setup

Absolutely no sense in swapping the guts from a 904 into a 999. The 999 has the 5 disc front clutch and should have, depending on the year the low gear set. What it may have that you don't want is the lock up torque converter. What you need to make it a non lock up is a non lock up input shaft from a mid to late 70's non lock up tranny. If possible get the reaction shaft also. You can convert the lock up reaction shaft by removing one of the balls that seals a passage but you can't convert the input shaft.