M3eater wrote:
All GM "small block" V8s look the same (with the exception of the new LS series and the LT-1s). Whether it's an old 265 cid, a more current 305 or 350, or a 383 (6.2 liter) or the 400.
Yours will either be a 305 (5.0 liter) or a 350 (5.7 liter) ... if it's a V8. If it is a V8, it's likely a 5.0.
Are you sure that it's not a 4.3 liter V6 (also GM, and very common on this boat)?
It is definitely a V8. I ordered an OMC factory service manual and I'm awaiting its arrival. As far as I remember the 305 and 350 are identical in size, it is the bore diameter that affords the larger displacement of the 5.7 liter. I will try and find the engine ID tag this evening.