30 L OMC Swap

"I have a '87 Rinker 17ft.

"I have a '87 Rinker 17ft. that originally had a 3.0 Liter OMC 4cyl Cobra outdrive. The engine has a cracked block, and I'm shopping around for another, but does anyone know if I'm OK just replacing it with a OMC 2.5L or 3.0L of any year if I want to keep the original outdrive? Most of the ones I'm looking at are from '78 to '90.

I've been told that I could also use a Mercruiser 2.5L or 3.0L since it uses the same block, but would need to change the belhousing, intermediate drive, and exhaust/intake manifold. Is that true? The Mercruisers seem easier to find, but I'd rather go with something that would bolt in easier.

Thanks!

Paul"

"The basic engine is the same

"The basic engine is the same in all of these cses. Can't you just swap the parts over?

Jeff

PS: If it were me, I'd spring for a new long block. You'd be better off in the end."

"I thought so, most of the par

"I thought so, most of the parts for these engines seem to work regardless of year, or if it's an OMC or Mercruiser engine. You'd think it would work fine.

Yeah, a new long block seems like a good idea. My other thought was to rebuild something that wa already running, though I'd need to find it for the right price and actually get the time to do it. Thanks for the input.

Paul"

"You want an engine or block o

"You want an engine or block older that 1990. You can go back to 1964 or so. But any newer than 1990 (including buying new) and you will run into problems with your 1987 drive coupler bolting up to the crank - they changed the crankshaft and rear main seal design, and the bolt pattern changed. GM= Gimme Money.
There's a conversion coupler *I think* for Cobra drives and you hafta change flywheels I think.
For 1985 and earlier OMC's there's NO conversion parts to the newer engine.
Other than that.... any 2.5L or 3.0 GM marine engine from a Mercruiser, OMC, Volvo Penta, or even Yamaha stern drive will work."