Originally Posted by CarsByCarl
Pilot hole is in the crank. The splined input on the trans will be the same on all C6's.
Some of the early C6's have a 30-30(I believe this is correct count) spine count shaft that can be put in both directions. Later input shafts have different spine count on each end, so that they can't be installed backwards. If you have one of the old 5 clutch foward drums and the old shaft, keep them together, as the shafts are hard to find now, and be sure to install the long splines to the rear of the transmission.