I know the OMC and Mercruiser engines 4.3L V6 are the same except for the dressings.

As was previously mentioned elsewhere on the boards my father who was the marine mechanic in the household passed away and I am trying to work out how to do a finish a project for a friend now that my father has passed.

We have an engine save for the power steering which is OMC will be running mercruiser pulleys/pumps etc. I know the Mercruiser and OMC exhaust manifolds are slightly different in the way they are plumbed. From what I have been able to figure out my father was planning using Mercruiser Manifolds to an OMC Cobra. I came to this conclusion from parts lying around. This was a severe budget job for a friend of mine.

Before I go any further can I use the mercruiser set up save for the power steering pump to run to an OMC Cobra?

I know my father did something similar years ago with a 454 to a King Cobra but I'm not sure how much of a hybrid it was at the end of the day.

Basically looking for help/advice with out spending money re-doing the boat for a friend as like previously mentioned this is an extreme budget boat.

What was the original problem with the omc motor?

His kids over heated it and cooked a couple of pistons. It was a 4 cylinder though. At this point old motor is out of the question.

We had the V6 lying around in the shop and sold it to him as a favor. Like I said my dad knew how to do it, I'm trying to figure this out and looking for advice on how to put it together as to how my old man would have.

Sounds like quite a project, you will have to figure out how to mount the front mounts to the stringers, thats work on the boat its self, if you can post a picture of what parts you have for this swap it would help a lot

Will keep you updated as I get the boat in the shop. Should get it in the next couple of weeks over the Canadian Thanksgiving.

The boat was supposedly cut initially for a v6/small v8 being a large bow rider, so we will see when the boat arrives.

boy do you have some work ahead of you...you may want to take a measurement and see if you can even bolt up a v6..the 4cyl models have a differant stringer layout..the 4 cyl mounts on a frount mount and the v6 mount on the sides..you may be doing glass work..

I have a question on motor mounts.

I believe there is a set from a 350ci omc I have kicking around. I know mercruiser is universal on the motor mounts between the 4.3, 5.0, and 5.7. Is OMC as well, or do I need to find a set of front mounts for a V6? I'm fairly certain I need to use OMC mounts with a OMC gimbal, I can not use merc mounts. or can I?

A little bit of glass work will be ok, be good to learn how to do this stuff now anyways.

fix is right. mounts themselves are the same from 4.3 to 454 on up. but there may not even be a stringer in the right place to put them. there PROBABLY is though. if this boat was ever sold with any i/o bigger than the 4-banger, they don't usually use 2 diff stringer designs. put a set of mounts on the engine you wanna use. measure distance between them. measure distance forward from rear mounts. go to the boat you want them in and see if they are gonna work. if it looks doable, hang the motor in place and get an alignment tool and see how much doing it will be to get engine leveled correctly. now, if THAT'S gonna work, you need to start shopping ebay for a Cobra exhaust y-pipe.there are several designs. you need to see IF there is one that you can make work with merc exhausts. i tried a couple of years ago with a 350 set-up and it looked like i woulda hadda make a custom elbow to mate them up. although thru-hull will obviously work...good luck. you might need it.