Can I buy a used 302 and use parts from my bad motor to convert it to marine?

[cameron92]

Bought a boat on marketplace only to find out I got scammed.

Seller put fresh oil in so it looked good. I took it out on the lake and now there's water in the pan. Not sure where it's getting in. I took one compression reading on the plug I could get to and not sure if I did it right but I got 100psi which is low.

Wondering if I can buy a used 302 for a car and convert it easily with the parts I have from this motor. The motor I have is EFI 1993. Model 50FAPRJVN

 

[Scott Danforth]

first, check your exhaust manifolds. most of the time water getting in is from failed exhaust manifolds. Check that first

do a leak down test to see if you have rusty valves from a leaking manifold BEFORE you fire off a parts cannon

most automotive 302 motors share a few parts with the marine motors. Truck motors are much closer to spec. the marine motor is normally using a 351 Marine cam and the better HiPerformance GT40 heads which is not what you will find in your average mustang

If I were to recommend anything retaining Ford and OMC, it would be get a 347" stroked short block and have your heads re-conditioned. then pull the EFI and toss it for a Mallory YLM distributor and a good 4-barrel manifold. Add heat exchanger cooling while you are at it.

Or get rid of the Ford/OMC powerplant and get a Mercruiser or Volvo Penta long tail

 

[Lpgc]

Yes you can. Probably a different cam, water pump, headgaskets, distributor, oil pan, etc but you can use parts from your engine.

I might've done the same instead of rebuilding my boat engine but I'm in the UK and used 302 Windsor engines are not as available over here so I rebuilt mine. If I had wanted an already rebuilt / upgraded 302 it would have been no problem, if it was a more recent 5L Ford from a late model Mustang etc that I wanted, or if it was an old Chevy engine there would have been plenty to choose from over here. I was surprised I couldn't buy an old used Ford Windsor, seems the rebuilders buy any old Windsors usually before they're seen up for sale by most other people.

Post crossed with Scott's. My 95 Windsor just has the E7 heads but I replaced the exhausts during the rebuild, it was cracked exhausts that killed it in the first place.

 

[Lou C]

Agreed you need to do a couple days of investigation first. Pull off the manifolds and check them, see if you have rust trails in the bottom of the water passages....that can put water in a cylinder and into the oil
Then pressurize the cooling passages with air and see if it holds pressure (12-15 psi)
You can also do a compression test/leakdown test and see what that shows
If you have to pull the engine, and could get a Merc or Volvo long tail with a carbed 5.7 V8 you'd be miles ahead.
Make sure though that the rest of the boat is structurally sound, the deck, transom, engine stringers, stringers outboard of the fuel tank, etc.

 

[cameron92]

Other side. Will do compression next