OMC used two 350 cu. in GM engines. The lower horsepower version was called a
5.7 litre and used with a Cobra drive. The higher horsepower version was called
a 350 and was used with the King Cobra drive. So, the recommended drive if you
go to the 315 hp engine would be a King Cobra and using a Cobra drive on
anything over about 275 hp would be questionable.

NoOne N Particular wrote:

My boat has the OMC Cobra 5.7L 260HP engine. At least it did. It sprung a
couple of water leaks and took out the heads, manifolds, and block. Anyway,
I am finally getting around to replacing the engine and I am considering the
new 350 Vortec engine rated at 315HP. From what I have been reading, it
should bolt right up ok, and all of my old mounting brackets should still
bolt up ok, but can the outdrive unit safely and reliably handle the extra
55 HP? And is there anything else that might come up and bite me in the
butt?

Thanks