Ona-Mission

I'm asking this question for the buyer of my 91 27' Fountain. a couple issues have been pointed out and I wanted to get the power of OSO members involved. He was told that a couple concerns and the first being that the heads don't have enough head bolts and that this is proned to blowing head gaskets? and the next is that the crank should be steel and not cast?

In my uneducated perspective I can see that these could be true as a week link from too much boost. Can these limits be identified or should improvements just be made as part of the prochagers installation?

Any other tips, big and small are appreciated. thanks in advance.

trc2

A stock 502 should hold up if he only goes up to a 5 psi boost any more and I would say he will have trouble I have a bunch of friends that have 5 psi super chargers on there boats and have had 200 trouble free hours on them I'm doing a set on my scarab right now have not run them yet mark at precision marine is starting on the second one next week If he does do the pro chargers I would say he should have the motors pulled and sent to a good engine builder and have them installed and dyno tuned thats the right way to do it I had a marine center tell me they could do it and all they did was f**k it up

Jeff P31

I agree with trc2 , the dyno is the place to do the tuning not on the water or a hose. They are NOT a bolt on and go part . You will spend the money one way or an other just a lot easyer doing it right the first time.

BAJA WILL

We never had good experience with pro chargers in boats, great in cars.

a 1991 502 carb is probably only putting out 400 hp at most, I would suggest pulling it and send it to a professional builder. For what the procharger / Installation and 93 oct fuel will end up costing, probably beyyer off just building the motor up.

Good builder will get that 502 up to a "reliable" 500hp on 87 oct.

WILL

Ona-Mission

Great advice.
I belive he plans to be conservative with the boost. Is the possibility of adding head bolts a real option? If creating more then 5 lbs what will be the first to break?
How do you feel about the stock exhaust? Will this be able to breath with minimal boost?

Sunshadow

Agree with Baja Will. I had prochargers on my last boat. $$$ will be better spent on good engine parts.

Ona-Mission

what are the bad experiences?

Jeff P31

Do not get me wrong you can make lots of power with them. I run them on hp500's and make over 740hp & over 800 ft. lb torque. But they where done on the dyno not in the boat . The first thing to break will be the outdrive !!!!!!!!!!! Good luck with your project . Jeff

Elite Marine

I have a nice M-1 with intercooler set up for the 502 EFI if you are interested.


The engine will be fine with the proper set up and low boost.

Ona-Mission

new or used?