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383 stroker build

Returntrip

Contributing Member
Hello everybody, Im looking to build a 383 stroker from a running 350ci chevy im removing from my boat. I would like to achieve around 375hp with a decent low, to mid range torque curve. I was hoping to use a set of 906 heads i already have, but i have no problem buying new, either cast iron or aluminum. IM leaning towards a roller cam with close to .500 lift with low 200's duration & around 112 overlap. Ive heard i should be concerned about Quench??? and piston type and selection of lower end components. Im also having a hard time finding a machine shop in the massachusetts area to even talk to about it. Is there anybody that could help me with choosing the right components to build this engine & what i should tell the machine shop what i would like to have done? Or even a book about the build with specs?
Im a little weary of buying an engine from one of those on-line advertisers. maybe someone knows a place to buy a good long block and i would go that route. Im working with around a 4,500 to 5,500 dollar budget. Any info would be helpful. Thank you.
 
Thanks for replying, I think that might be the book i wanted to buy. I saw the price and almost fell over. If not mistaken, i think the price for the book is 7 to $800???? Please tell me Im wron....
 
Sounds like you wanna build a performance car engine and drop it in your boat. Does not work like that. You want more go, you need bigger engine than a 383. All that you are talking about for your current engine might gain you a couple mph more at the top end, but don't expect much. it'll run out of breath about the same as it does now.
If you want speed, you need a 454 or larger, and a propeller that is matched to your boat. Even now, I would start by doing some propeller matching with a competent prop shop. This alone will make more sense than spending money on useless things like roller rockers.
I'll add that you will spend roughly 50-75% more on a rebuild of your current engine than you would buying from a reconditioned engine supplier. With trade-in, it can be very attractive
 
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Thanks for the input. I agree with you about the roller rockers. I’ve always been a big advocate of big block torque & power. Due to limited room in the engine compartment & already having several small block engines I was hoping to make something I have work without changing a lot of hardware to go the big block route. I’m a little wary of these high production engine rebuilders-distributors. I turn wrenches 65 hours a week on diesel fishing boats & don’t particularly enjoy using my off time doing many more hours to doing a re-fit on mine. If you had to go the route of installing a drop in engine package who would you recommend Mr. o2batsea?
 
Honestly, unless this boat is some family heirloom with huge sentimental value, I wouldn't spend the coin on a repower. You're looking at 15 grand at least for that, and you can buy a nice used boat that is more your style for that kind of money. Take what you have, get it in shape to sell and start looking for your next date to the ball.
HOWEVER, if you must keep your current boat the way I would go is to hop on down to your Mercruiser store and see what they can do for you for a drop-in repower package. They offer both new and remanufactured engines. These are fully warranted, are professionally installed and you can upgrade to CAN-bus instruments and controls. It can all be financed through them or with other lenders. They have a nice Fuel Injected 383 showing on the website. This gets you back on the water much faster and without all that much effort on your part. Well, except for paying for it of course
 
Can you use a 1 piece rear main seal crankshaft in a 2 piece rear main seal block? I know the flex plate bolt pattern is different, and main cap. But will older block accept the aluminum housing for a 1 piece seal?
 
with the correct adapter, yes.....

I don't know of any reputable builder that would use the two piece block instead of a one piece block ...
 
I was only asking, never rebuilt any gas engines, not even Chevy. I got a 1 piece rear main seal block anyways. I wanted to use the 377 forged stroker crank i already have. How about what design piston to use with 906 Vortec Heads? I heard D shaped with 2 valve reliefs possibly? instead of dished or flat. For good Quench.
 
The engine thet is coming out of the boat was unsure if it was a 1 piece or 2 piece rear main. Doesn't matter anyways, the previous owner never winterized it right, the block cracked. I got a one piece, 4 bolt main block from another mechanic i work with, thanks.
 
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