Im looking at a 1976 Mark Twain with a 302. Other than the asessories, waterpump and such is there any difference than a regular automotive 302?
It ran last year and the owner claims it wont turn over now. Im just wondering if there are major engine problems if i can just swap in a regular 302 and bolt everything up.
Im going to look at it in a couple days.

Thanks

Tony Warren
Nebraska

 

Guess what, been there done that. The boat motor I changed with had a warped block and bent rod(water doesn't compress DUH!). But the heads, pistons, valves, springs, crankshaft where all reused(from the new engine). Yes, if it is a 302 every bold hole will be there.

 

Thanks, just didnt want to get myself painted into a corner.

Tony Warren
Nebraska

 

How much would a new (rebuilt) 302 run me?

 

HI,

The Boat engine is the exact same motor as a truck 302. But more power.
The compression is not the same. The RPM is not the same, The cam shaft is not the same. frost plugs are probably made of brass.

But yes it will run in your truck. It's just that the RPM in the boat Engine is different.

 

I should have clarified, im not wanting to use it in my pickup, im just wondering what will interchange so i can get the boat going. It seems there isnt any difference in blocks, just components.
Do the mercruiser 302s use more of a towing type cam? I figure if i have to pull the thing apart, i might as well change it, and the lifters.

Im new to the Ford smallblocks, ive only done 400Ms and 390s.

Thanks

Tony Warren

 

When was it last running alright? Somtimes if you dont flush it out and it has a leaky block the piston can rust up.... Happend to my dads boat.

Also anyone know? How much a new (rebuilt) 302 would cost me? and what would usaly come with it?

 

Ok. I will explain what i did with my Boat.

It's a bit different but probably the same.

Power Boats with OMC engine and Stern Drives Normally comes with Ford engines.

Power Boats with Mercruiser engine and Stern Drives Normally comes with Chevy Engines.

For my boat , I had a 302 Ford. The engine was a Total wreck so I've replaced it. Unable to find a Ford engine I had to put a 350 chevy 260 HP. I also had to change the manifolds and Risers , cause they where leeking and caused the water to get into the engine and rust everything. The Chevy engine will work on the OMC stern Drive. just make shure you have the manifolds and risers that match with the engine.

But go with a Ford Engine. Way better. I personnaly don't like Chevy or anything else . Has to be a Ford. Built for Thought.

An ordinary engine from a truck will do for a Boat. but make shure you put some brass frost plugs. you don't want those frost plug to rust. The RPM won't be the same. so don't push the engine to hard. If you really want to push that engine to the max . I would go ask a Marine Engine rebuilder. They will be able to tell you exacly what kind of Cam, Heads , etc ... that you might need to rebuilt that engine so you can push it to the limit.

Remember a truck as a transmission that allows the motor to lower RPM everytime you change gear. But a Boat doesn't have a transmission so the RPM is getting higher everytime you push on the trottle. So that engine as to be built for it.

On a truck the engine doesn't have to strugle after it reached his speed. it just have to maintain the speed and that is not hard on the engine, but in a boat it's different. to keep you speed the engine as to stay at the same RPM and it's hard on the engine. that's why it has to be rebuilt with a different configuration.

I hope this can help you. My best advise is to go at a marine engine rebuilder and ask them what exactly you need.

 

I plan on staying with a small block ford. If the 302 is toast, ill step up to a 351W. Got a couple of those lying around.

Tony Warren
Nebraska