I have a 1987 Scarab II with 454's in it. Both motors are turning clockwise. I was wondering:
1. If I am able to change the rotation of the drive without changing the whole lower unit?
2. How I would go about doing this and where is the best place to get the parts needed.

What kind of drives?

Alpha 1 drives.

Takes a counter rotation gear housing (lower unit). You can't just run an Alpha in reverse like a Bravo.

You would have to change the drive or at least the lower unit on one of them.

FYI the Alpha drive was only availiable for 2 years for use with the 454. They never held up well to the torque of the big block so the Bravo came into play.
Here's a link to a site where it's mostly Alpha and Bravo guys. I'm sure you can get a lot more Alpha information over there.
http://forums.iboats.com/

The change is made in the lower unit, no need to change the entire drive. I am not sure if you can change internals and use the same case, or if the case is different as well, likely a good drive guy can answer that for you. Had this done many years ago on a 32 Pachanga with 454 / 330's. I put 550 hours on that boat over six seasons and never had an issue with the Alpha drives.

Wish I could say the same about the Bravo's I've owned since then.

Thanks for the input, now the question is where to buy the parts needed to make the change, any suggestions?

IMO Do yourself a favor now and start looking for a set of Bravo's. You can pick up a set of drives and gimbles for cheap from someone doing an upgrade and save yourself the aggravation of having to repair the Alpha you just spent $ on. The Bravos will hold up better than the Alpha's, their nothing great either just a bit stronger and it's a pretty simple swap over.

Remember that a straight swap for Bravos will loose the OP some speed as a favor for giving him a more robust drive in his application. Yes, most 454/330/Alpha combinations blew up a long time ago. But, if you've very careful with them and have a relatively light boat, they can actaully last. One guy up here has a 22' Pachanga with that combination and it's never blown up. Of course the guy babys the hell out of it ..

If you plan to stick with the Alpha you might want to check these out.
http://www.sterndrive.cc/mm5/merchan...ercruiserAlpha