Horse Power Loss ?

The big factor in drivetrain loss is friction. You have to reduce friction to get any gains. There are some tricks but to do most of them, you better know what you are doing. You can run lighter fluids in the rear. Changing from ball type bearings to needle type bearings will help. As was mentioned, anything that is being run buy the engine, (power steering, fan, alternator, a/c) all drain off horse power. Just swithing from a 727 to a 904 tranny will save about 30 HP. Even the U-joints can drain off some HP if they are installed wrong. The tires you use can have more rolling resistance than others. And on and on it goes. There is HP inside the engine that is waiting to be freed up as well. By swithing to a roller cam and rockers from a flat tappet of the same size you will free up HP just because of less fricton. It's just a matter of where you want to start.

Jack