With the engine rebuild I am planning for my 1980 377 flatdeck Scarab, Im guessing that I might get 750 HP out of the twin turbo 454 engines. Even if I fall short of that and am in the 650 hp range I'll be happy. But the biggest problem is the drives. Right now I have TRS. Ive thought about going with SSM III's but the used price is up there. I plan on redoing the transom sometime in the next 2 years too and was thinking of doing Kaama drives on it. How much power can the 502 trans hold? How much power can the drives hold. I understand it it considerably more than a typical stern drive because you don't have the gears in the lower unit to contend with.

My understanding after researching the same thing led me to believe the Kaama setup is happiest around 700hp and keeping the rpm as low as you can.

As I recall, Kaama would guarantee their drives up to 600 HP.

That would make sense to give them a bit of cushion. The most knowledgeable people I could find say 700 is safe. The lower the better rpm wise to help keep the transmissions happy.

I was always told 700hp and 6000rpm was their limit, however I have several friends that "exceed those design perimeters" and they have run (and still run) them hard for years without even a hiccup.

Do you know if a transmission other than the MG 502 was ever used?

Anybody have input on how they might work on this hull?

Get in touch with Hblair. He has a restoration thread going on his 38 in the Scarab section. He's talked first hand with the owner of a 38 with arnesons and Dan M. as well regarding this hull and surface drives. I believe he found out it should be acceptable.

I have never heard of any Kaama with anything other than the Twin Disc MG502.
My understanding is it is basically their folklift tranny, and it's disc packs are designed to run either way without a difference, so you simply switch the lever and change rotation. They eat a little horsepower, but they are bulletproof!

I've heard the forklift thing before and don't believe it at all. I believe it's a dedicated marine gear (MG) that's designed for hundreds if not thousand of hours use behind commercial diesel applications. That's my 2 cents anyway