377 mag

[99xcss4]

if you only want the intake or part of the intake check out this thread I post a literal boat load of them that I found on ebay do not know if any of them are still up for grabs or not though https://www.gmt400.com/threads/unable-to-post-in-iso-section-l31-marine-intake.67250/

 

[Trio]

The engine has 612 hours on it. Did some searching and they say 1 hour is roughly 100 miles in a vehicle.

"They" say 100 miles per hour? for a boat?

 

[thinger2]

I saw an ad for a used Mercuiser 377 Mag. It appears to be a Vortec block with a 383 stroker crank based on what I have read. It has the rare Vortec marine fuel injection intake.

Totally clueless about boat motors. Can I just yank the exhaust manifolds, engine accessories, etc. and drop it in my 96 Tahoe? Will the crank accept a flex plate?

Be very very spooked about any used marine engine.
Pulling a boat engine is not easy.
The normal cherry picker doesnt have the reach to pluck it.
It aint easy so why did they bother doing it?
Any marine engine especially in a high speed hull is subject to much more wear and that wear happens much more rapidly than in a car.
We call it crank shock or crank bounce.
In a drag car once you get traction and put torque through the power train that load ramps up in a pretty steady way and obvserable way.
In a boat Crank load and rpm are subject to not only the engine slamming up and down.
But the constant loading and un loading of the prop as it comes out of the water.
The other problem with used boat engines is that I without a doubt can guarentee you that engine has hit 6 grand or maybe more while some drunk dope tried to drive up on a bone dry bunk trailer.
And the stroker makes it much worse.
Stroker valve trains will come apart at high sustained revs.
Especially if there is no load on them.
Twin engine 850 horse ******* kabloo crying because the props were halfway out of the water
They blow up when chuckleheads try to power the boat onto the trailer.

Never ever ever frigging ever buy a used boat engine.
They probably yarded that **** motor out of a crap boat and found out that it will 600 or 800 bucks to landfill the boat and are trying to cover the cost by selling you a "marine" engine.
The only "marine" part of that engine is the exhaust manifolds and the intake and the starter and water pump and alternator.
The rest of that engine is a bone stock weak cam low compression engine designed to run on 87 octane because the only thing you can buy at a marina is 87 octane.

 

[L31MaxExpress]

Be very very spooked about any used marine engine.
Pulling a boat engine is not easy.
The normal cherry picker doesnt have the reach to pluck it.
It aint easy so why did they bother doing it?
Any marine engine especially in a high speed hull is subject to much more wear and that wear happens much more rapidly than in a car.
We call it crank shock or crank bounce.
In a drag car once you get traction and put torque through the power train that load ramps up in a pretty steady way and obvserable way.
In a boat Crank load and rpm are subject to not only the engine slamming up and down.
But the constant loading and un loading of the prop as it comes out of the water.
The other problem with used boat engines is that I without a doubt can guarentee you that engine has hit 6 grand or maybe more while some drunk dope tried to drive up on a bone dry bunk trailer.
And the stroker makes it much worse.
Stroker valve trains will come apart at high sustained revs.
Especially if there is no load on them.
Twin engine 850 horse ******* kabloo crying because the props were halfway out of the water
They blow up when chuckleheads try to power the boat onto the trailer.

Never ever ever frigging ever buy a used boat engine.
They probably yarded that **** motor out of a crap boat and found out that it will 600 or 800 bucks to landfill the boat and are trying to cover the cost by selling you a "marine" engine.
The only "marine" part of that engine is the exhaust manifolds and the intake and the starter and water pump and alternator.
The rest of that engine is a bone stock weak cam low compression engine designed to run on 87 octane because the only thing you can buy at a marina is 87 octane.

Except it is stroked and probably has a forged 3.75" stroke crank and could be the GM 3.80" 4340 one as well depending on the serial number.

 

[Spareparts]

I have had several Inboard boats with either Volvo Penta or Mercruiser power train. I have a small hobby of buying old boats that need a little work for cheap. New interior, Rebuilt stern drive kinda stuff.
Buff and wax sell for 2-3K profit after using all summer.
If that engine has good compression, No crack's on the block, Freeze plugs intact, Plugs look good i would use it with out hesitation.
Fresh water engines last forever with proper maintenance but if its a saltwater engine -RUN

 

[KansasOBS]

$2500 is ooof. For that or a 6.0. That's about what the all aluminum 6.2 LS's run, or at least around here.

 

[0xDEADBEEF]

"They" say 100 miles per hour? for a boat?

Some random website. I know boats get a lot more load than a car/truck would. What is your estimate of 612 hours in boat vs in a vehicle.

 

[L31MaxExpress]

$2500 is ooof. For that or a 6.0. That's about what the all aluminum 6.2 LS's run, or at least around here.

$2500 would be a great price for a running 6.0L here. 6.2L brings over $4K. The best buy here is a L8T 6.6 and 6L90E pullout, those can be had for $5-6K with less than 20K miles. A Marine 377 for $2500 is a very fair price, the manifold itself sells for over $1,000. If it has other marine bits like the harness, ECM, bellhousing, accessory brackets and exhaust manifolds they bring a good chunk of cash when sold on Ebay. I paid $800 for one with freeze cracks sold the good external parts and doubled my money, that was keeping the marine intake manifold, camshaft, lifters, Vortec heads and HT383 rotating assembly.

 

[0xDEADBEEF]

if you only want the intake or part of the intake check out this thread I post a literal boat load of them that I found on ebay do not know if any of them are still up for grabs or not though https://www.gmt400.com/threads/unable-to-post-in-iso-section-l31-marine-intake.67250/

Some of those are V6 intakes, missing fuel rails, etc.

 

[0xDEADBEEF]

Anyway, I appreciate all the replies. Let's see what the compression test shows. Maybe I can wear him down more, LOL.