383 conversion
03-27-2019, 08:28 PM
#11
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Chas,
Car and boat are two totally different animals.
Many many years ago someone told me that running an engine in a boat was like taking a truck with a stick shift trans, putting it in high gear and finding the steepest hill you can find and drive up that hill at WOT and ..... the hill never ends
In a car the engine is at max load for only seconds at a time. In the boat it is there all of the time. Sort of like putting it on a dyno and loading it down and keeping it there for an hour.
Car and boat are two totally different animals.
Many many years ago someone told me that running an engine in a boat was like taking a truck with a stick shift trans, putting it in high gear and finding the steepest hill you can find and drive up that hill at WOT and ..... the hill never ends
In a car the engine is at max load for only seconds at a time. In the boat it is there all of the time. Sort of like putting it on a dyno and loading it down and keeping it there for an hour.
03-28-2019, 07:02 AM
#12
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Fix what’s there. Can’t be any more than a carb or ignition if the engine is ok.
It could be junk though. So thinking through swapping your camaro motor isn’t a bad idea.
If you have a real deal measured 500rwhp 383 you must have some 210-227cc heads and a lot of cam. If you run wet exhaust you’ll need something very mild like sub 220 duration at .050. If you can go dry you could run it up in to the 240s but it’s going in a fishing boat so I don’t see the point. At that point the heads are far too large but probably not hurting you much. An RPM air gap would probably make them work fine.
If you current head gasket is .098 I don’t think you can drop compression much. Thickest I’ve seen is .120? If you can’t get compression to 10 or less you need to pull timing and under prop it so the load planing off is lower.
So you may need a 76cc head with a sub 200cc runner and new cam. It’s starting to add up. Unless you want to self port the chambers on your heads for the budget approach.
It could be junk though. So thinking through swapping your camaro motor isn’t a bad idea.
If you have a real deal measured 500rwhp 383 you must have some 210-227cc heads and a lot of cam. If you run wet exhaust you’ll need something very mild like sub 220 duration at .050. If you can go dry you could run it up in to the 240s but it’s going in a fishing boat so I don’t see the point. At that point the heads are far too large but probably not hurting you much. An RPM air gap would probably make them work fine.
If you current head gasket is .098 I don’t think you can drop compression much. Thickest I’ve seen is .120? If you can’t get compression to 10 or less you need to pull timing and under prop it so the load planing off is lower.
So you may need a 76cc head with a sub 200cc runner and new cam. It’s starting to add up. Unless you want to self port the chambers on your heads for the budget approach.
Chas,
Car and boat are two totally different animals.
Many many years ago someone told me that running an engine in a boat was like taking a truck with a stick shift trans, putting it in high gear and finding the steepest hill you can find and drive up that hill at WOT and ..... the hill never ends
In a car the engine is at max load for only seconds at a time. In the boat it is there all of the time. Sort of like putting it on a dyno and loading it down and keeping it there for an hour.
Car and boat are two totally different animals.
Many many years ago someone told me that running an engine in a boat was like taking a truck with a stick shift trans, putting it in high gear and finding the steepest hill you can find and drive up that hill at WOT and ..... the hill never ends
In a car the engine is at max load for only seconds at a time. In the boat it is there all of the time. Sort of like putting it on a dyno and loading it down and keeping it there for an hour.
On a side note I do have a 5.3L (LS based motor) truck block just sitting in the garage if you guys think building that for the boat is a better option. I can go that route with stock truck heads and cammed. It's a low mileage block that came out my truck when it started having issues (hydraulic lifters failed). If I remember right it only had 68k or less on it with no noticeable ridge on the cylinder walls. Either way I have a few options just figured you guys with the performance boats would be able to point me in good direction. I don't mind spending a little money on the boat just want the best option. I could probably get the 5.3L up and running for around $1500-$2000. I have $2000 invested into this boat, and trailer where it Blue Books for $8000. I don't want to spend more than $8000 total invested.
So the current consensus is don't de-tune the current motor I have in my Camaro cost too much and just plain too much motor. Try and get that one in there started and go from there.
