OMC v8 engine swap

[Sbushman]

I am new to working on boats and have a project ahead of me. I have a 1977 slickcraft ss-235 with a omc 190 hp motor. I found out the block is cracked. But I do also have a 1979 omc 260 hp engine that runs. I was wondering if I can just put the 260 hp in and be ok. Or is there more too it. And help would be greatly appreciated.

 

[Scott Danforth]

The 190 is a 305, the 260 is a 350. Go ahead, it will swap over.

 

[Bondo]

Ayuh,..... Welcome Aboard,.... No problem so long as 1 of 'em ain't a Ford,....

Are they both Chevy,..?? distributor aft,..??

 

[Scott Danforth]

Good point, keep forgetting OMC used both Ford and GM dusting the same years

 

[Sbushman]

I'm pretty sure the 190 hp is a ford 302. Is that going to make a big difference?

 

[Scott Danforth]

I'm pretty sure the 190 hp is a ford 302. Is that going to make a big difference?

yes, ford stuff only bolts to ford stuff, gm stuff only bolts to gm stuff. so you would have to swap over everything - motor, flywheel, exhaust, and intermediate housing on your OMC. the stringer outdrive wont care either way, however the intermediate will.

 

[VE8EV]

This won't be too hard IF you have all the pieces that go with the 260. If the boat is a 1977 then the 190 (if it is original) will either be electric shift or hydro-mechanical shift. The 260 will be straight mechanical shift and it will have a different ratio in the upper gearcase. Unless you can swap out everything pulleys-to-prop (which on an OMC is very easy) and also swap shifters and cables then you should probably look for something more compatible with your existing setup.

 

[Sbushman]

That's what I was afraid of. I did see that the 260 hp has the intermediate section attached to it. But there's a lot of different connections compared to my 190 hp. And it doesn't have any controls or cables with it. Thanks for all the help. I'm kind of lost when it comes to boat mechanics.

 

[Sbushman]

Can i just swap the engine and bell housing and keep the rest from the boat?

 

[VE8EV]

Hard to say without seeing what pieces you have from each. Probably not is the short answer.

 

[Sbushman]

Thanks for all the help. I think I'm just going to start looking for another ford instead of the gm.

 

[Sbushman]

One more question. Will a 302 HO work? Or do I have to stick to the regular 302.

 

[VE8EV]

Not sure what the difference is between an 302 HO and a regular but I believe the OMC 190 is essentially a 302 with a 351 marine cam and 351 heads. So either a 302 or 351W will drop right in and all the OMC accessories will bolt up.

 

[Sbushman]

Ok. Thanks. What about the year though. Does it have to be the same as my 1977?

 

[Scott Danforth]

Pay attention to the firing order. If looking for automotive engines, look at trucks. The cam profile of a truck is closer to a marine motor. Out of curiosity, what is wrong with your current motor?

 

[Sbushman]

The boat wasn't winterized properly so the block cracked and is leaking water into the crankcase. And both the exhaust manifolds cracked too.