chas0218

Hi everyone, first time on here. I'm a new owner of a project boat. I'm a big time fishermen love it and was in need of a new reliable safe rig. I found a Florida ocean boat (Pro-line 241 with a frankensteined mercruiser and Bravo 1) for dirt cheap where the P.O. swapped a "Carmaro motor" into it and doesn't run right. It needs some work to say the least (supposedly fuel issue) but won't know for sure until I start digging around. Now here is where it's going to get interesting I have a 383 I built sitting in my Camaro that is on the back burner until I can get around to restoring it. Long story short I need the boat more than the Camaro right now and don't mind donating the engine to the boat. Now I built this engine to accept N2O the lower is fully forged (crank and pistons) with H-beam rods. The motor puts out around 500hp to the wheels (without the juice) of the Camaro when it was in service. Now I would like to take this engine and drop it into the boat. The cam is what had this motor humming along to 6500 RPM. I know I will need to switch cams and find a marine carb to feed this thing. I'm not looking to go fast but if she motors along that's a plus. I don't really care if I make 300hp or 500hp just want a dependable motor for this boat. I was going to scavenge all the parts needed for the marine aspect to add to this motor all while checking out the old motor to see if I can get a little machining done and drop it back in at some point.

So enough of the back story the million dollar question is....Should I use the motor I already in it not knowing it's actual operating condition or drop in my motor that I know runs well and is still fresh. I forgot to mention the 383 has maybe 1000 miles on it with no N2O ran through it yet and must be ran on high octane.

I'm new to the I/O world but working on engines is kind of my thing. I know the I/O isn't a car engine and needs torque more than HP. I'm open to any and all recommendations.

chas0218

I wanted to add that this motor is already shoehorned into this boat. To change the plugs I have to pull the exhaust manifolds. Not ideal but I'll make it work.

BillK

I would try to get the engine in the boat running first. That way you will know if you have an ignition or fuel system problem before you start swapping engines etc.

What compression is your 383 ? You will be hard pressed to find any type of high octane fuel on the water so you will have to be fueling up before you go out.

chas0218

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Okay I'll try that first, worth a shot. Current motor has the factory 2 barrel on it which might be contributing to the problem. From what I understand about the current motor is they paid a guy to swap over all the marine components to the "Vortec Camaro Motor". After the swap it wasn't running right and thought it to be a fuel problem.

The 383 is 11.5:1, right now it runs on pump gas but changing the cam I might have to go to a little thicker head gasket to keep it from knocking. Current cam has a long duration and bleeds off a little of the compression. I live in N.Y. all our pumps on the water are non-ethanol 91 octane so that side of things should be good. The main concern for me is swapping cams and having the compression a little high. I could always retard the timing a little to help but don't think that alone will be enough.

Trash

With 11.5 comp in the Camaro motor that is a bit high (way high in my book). With your RWHP numbers the cam is incompatible with wet exhaust too (which you mentioned). In my estimation you have just as much work de-tuning your 383 to get it to work as you do 'going over' your existing motor to get it to work. Regarding your 383 compression, cam and potential internal clearances may be an issue. The stoutness of the internals is not an issue.

highplainsdrifter

I'd see if I could get that motor that is already installed working properly.

You'd have some detuning work to do to get that high compression big cam motor to work well in that boat. Could be a can of worms and some $$$

Not to mention, it's spring. Might be a different story if it were November.

R

chas0218

Yeah very true, I'm a school teacher so no work this summer except this boat and have another I can run around but good point.

BillK

You might as well forget about that in a boat. You cannot get a thick enough gasket and that might actually make it worse. Around this area I tell people they are pushing the limit at 9.5 to one with iron heads and 93 octane.

The ethanol does not make any difference. 91 octane is 91 octane, period.

chas0218

Well we can get 93 with 10% ethanol at the pump. I have the current carb setup for 93 without any detonation or pinging issues and that is with total timing advance of 32* (Vacuum and mechanical). I have a variety of weights that I can use to adjust the timing curve and full advance with my current distributor. The 11.5:1 is the static compression ratio where the dynamic is 9.3. With a Comp Cam XM256 grind and .098 head gasket it puts the dynamic at 9.2 which should be able to run on 91 pump gas with a little less timing. The head gasket is not ideal thickness with large piston to bore clearance but should work long as the carb is tuned and not dumping excess fuel. I'll probably run the motor with no thermostat or a restrictor to keep things cool. Where I fish and boat the lake water doesn't get above 75* surface temp and cooler out further in the lake.

I am hearing what you guys are saying and I will try getting the motor that is in the boat running right first. This is all in case I can't figure out the problem with the current motor/get it running.

hogie roll