Ok Guru's, you educated me so well on part numbers, thanks by the way, that I thought I would up the ante.
On My twin 454 mercruiser 370's with borg warner transmissions and TRS drives, where does the reverse rotation occur? Is it in the drives, transmissions or engines? Is there anything special I should do when rebuilding the engines to compensate for the rotation?

In the drive.

Well, USUALLY in the drive, but not always. If you have one standard and one reverse rotation engine it will be obvious by looking under the hatch as they crank over. With opposite rotation TRS gearcases, one will have a small "RH" stamped in the end of the propshaft; the other will be marked "LH". If you have an oppostte rotation engine, then there are some considerable differences, including the cam and starter in the parts catagory. --- Jer

Ok, I checked the prop shafts, and sure enough, there is a LH and RH stamp on each. Does this mean I do not have to worry with the engines and just set them up as standard rotating engines?

Borg Warner trans can not take full power in reverse. The trans has to be set up internally to run backwards on a counter rotating engine. The trans will be connected to the shift cable exactly as a standard rotation setup.

You got 2 LH motors,standard rotation. Both motors will take same parts.

Yep, what he said. And no need to worry about the trannys cause they will both be std. rotation. If you really had opposite rotation engines, the gearoter housing on the B/W would have been indexed for that and you would NOT have been putting full forward power through the planetary gears. Just remember; when the time comes to rebuild the lower gearcases, they take lots or different parts. --- Jer

Thanks for all the valuable info, Maintaining the boat is much easier with you guys backing me up.

I'm quite sure you don't have a reverse rotation engine. I read in another post of yours about one of your motors was a Gen V and the other a Mark IV. The raw water pump on a Gen V is indexed differently and the in/out are not in the same location as the Mk IV. (I've dealt with this before)

Good luck,

Kurt

yes, to reinterate the opposing direction happens in the lower gears of the drive not the upper gears.