3.0 omc to 4.3 cobra

[metal249]

Re: 3.0 omc to 4.3 cobra

I have a 250 ci gm in my truck, would that bolt on to the cobra?

 

[Bondo]

Re: 3.0 omc to 4.3 cobra

Nope...

 

[Paul Ryan]

Re: 3.0 omc to 4.3 cobra

I think you might have missed what the thread I posted earlier said. It said you can not make a 3.0 drive into a V6/V8 Drive. They have differant lower ends. K so buy a new lower end. $$$ Then you have to question will that V6/V8 lower end bolt to you upper drive? I dont know...All this and you still have to change the gears in the upper drive. $$$

Your now seeing what I stated earlier about going up in number of cylinders for a I/O. I've taken 4 cyl out and drop V8's in the auto world alot. The auto world is nothing compaired to the marine world. Not even close!

Sorry just hate to see you spinning your wheels on something that doesn't look like it will work.

Also would like to state something mentioned earlier that you can not use auto electric parts in a marine app! Starters, Alternators etc....Don't ever forget this! The possibility of blowing the boat and you up is huge!

 

[180shabah]

Re: 3.0 omc to 4.3 cobra

As stated above, the 4cyl cobras are not as sturdy as the v6/8 drives. changing from an inline engine to a v engine will require the fabrication of new engine mounts IF there is even room to do it. Cobras, also use ESA, so you would need to get all of those parts with your new engine, purchasing them aftermarket will get expensive. Rebuilding the drive = more work and money, and you still have a drive that is getting harder and harder to maintain. They are also VERY VERY sensitive to shift cable adjustment, get it wrong and you will be rebuilding it again.

All of this time effort and money - your really need to consider swapping in either a merc or vp. they all use the same cutout in the transom, except for the Gen2 alphas(they have two additional mounting holes - no big deal).

 

[bear_69cuda]

Re: 3.0 omc to 4.3 cobra

I think you may also have issues with motor mounts. I wanted to re-power my 3.0 Bayliner and found I would need to modify the stringers, and engine mounts to make it happen. Not to mention re-gear the outdrive... Mucho cash... And time....

 

[Subliminal]

Re: 3.0 omc to 4.3 cobra

Has anyone ever considered a small centrifical supercharger with a few lbs of boost, rather than an entire engine swap? If one wanted to be creative, they could rebuild the engine and put better pistons in and run 4 or 5 PSI of boost, probably get another 30 or 40 HP out of the engine.

 

[ezmobee]

Re: 3.0 omc to 4.3 cobra

Moving to the I/O section....

 

[Lou C]

Re: 3.0 omc to 4.3 cobra

As others said there is no way this is worth the efffort it would take...and the cost...keep in mind OMC is out of business...not all Cobra parts are so easy to find...like exhaust manifolds (one piece) for the 4.3...if you like the boat and want to run it just keep the 3.0 and run it as long as you can...when it comes time to repower...convert the whole thing over to Merc....the parts are available and there's a marine mechanic in every town who can work on if needed...no so with a Cobra....take it from someone who owns one....

 

[metal249]

Re: 3.0 omc to 4.3 cobra

Thanks for the info guys, Just found a parts boat for $300 w/302 cobra!

 

[Paul Ryan]

Re: 3.0 omc to 4.3 cobra

Now you got something to work with!!!! Great price too. I wonder if your boat is rated for that HP? Is yours a Corsair, Sierra, Spirit, or Topaz?