The loss is a combination of frictional loss, efficiency losses, and inertia loss needed to accelerate rotational masses including the trans and rear end.
I like to think of things in extremes to help to understand them. Imagine a 4 ft diameter 250 lb flywheel. The amount of inertia required to accelerate this mass is going to be significant. The faster the flywheel is accelerated, the more power is needed to rotate the flywheel. The same principal holds for rotating the torque converter or flywheel/clutch assy, trans internals, driveshaft, ring and pinion, axles, and wheels/tires. So you end up with frictional heat losses, gear efficiency loss, and inertia loss. Inertia loss is one reason why a 9" uses more power than an 8". 100 HP loss through a drivetrain is not due to just friction. If it was, the heat generated would be tremendous.
A friend who has a built 289 with a toploader and built 8" behind it lost 15.5% from flywheel to chassis. 375 FWHP and 317 RWHP.
Tracy Blackford: Corona, Ca
'65 FB Mustang 331 with H-beam 289 rods, KB 322's, 282S cam, fully preped 351W heads. Built C4 and 3.50 9" posi
<font size=-1>[ This Message was edited by: blkfrd on 10/19/05 11:31pm ]</font>