[MrE]

Mike, thanks for doing my legwork on rear ends! I'm rolling the dice with mine. I know the 8V92 V8 two stroke turns higher RPMs than the ISM I6 four stroke. The 8V92 was coupled with an Allison HT 740 which has a 1.00 fourth gear ratio. My ZF is currently programmed as a 5 speed. 4th has a 1.00 ratio matching the Allison, and 5th is 0.83, I'm hoping that will offset the RPM difference.

1st - 3.43 2nd - 2.01 3rd - 1.42 4th - 1.00 5th - 0.83 6th - 0.59

If I decide to program it into a 6 speed I'll definitely be looking for different gearing.