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Discussion Starter #1
It can be had as a 620 HP 9.6 compression or a 750 HP 12.5 compression version.
One question I have is what is it about the engines that makes Chevrolet write, "This engine is not designed, nor intended to be used in any marine applications"?

Also...
Anybody use one of these engines?
How did it work out?
 

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It can be had as a 620 HP 9.6 compression or a 750 HP 12.5 compression version.
One question I have is what is it about the engines that makes Chevrolet write, "This engine is not designed, nor intended to be used in any marine applications"?

Also...
Anybody use one of these engines?
How did it work out?
Likely piston to cylinder wall clearances , and actuarial obligations due to what might be considered extreme useage by the producer (warranty/guaranties) are at the heart the issue
 

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It can be had as a 620 HP 9.6 compression or a 750 HP 12.5 compression version.
One question I have is what is it about the engines that makes Chevrolet write, "This engine is not designed, nor intended to be used in any marine applications"?

Also...
Anybody use one of these engines?
How did it work out?
We have used the 572 ,But before you install the engine a few things have to be addressed. Cylinder heads have to come off and have the valve guide clearance opened up. Mains and rods should be checked. The oil pan and pickup have to be change in order to fit in a jet boat. Jetting has to increased by 4 numbers front and back on carb. It comes with a vaccum distributor do not use the vaccum advance and have the distributor recurved. Other than that it is a drop in.
 

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Discussion Starter #5
OK More questions then...

I understand clearance issue. Makes good sense to open 'em up a bit for an engine that is loaded the way a jet (or any boat) loads an engine. And I can understand any warranty issue. I didn't know GM had a warranty on an engine like this.

I had another question about the engine combo...
It's a 4.375 stroke and 4.560 bore for the 572 inches.
Is this better or not than the square 4.5 x 4.5 572 combo that I wanted to build.
Just looking for options here.
Buy it all in one crate or build it myself.
 

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Been running a 4.375 stroke by 4.56 bore for years now. Tall deck preferable. Better rod angle and lower piston speed. :thumb:

I put years of boating on a 502 / 502 gm Shortblock that I put a set of AFR 305 heads on and a solid roller cam from Chris Straub. I ran two Holley 750s on a dart tunnel ram. It made 740 hp on pump gas 9.2 to 1 compression even ran about a dozen bottles of nitrous at a 150
Shot through it. After 5 years I took it apart to make it a 540. The bearings were perfect. Had I known I would have left it a 502.
 

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I understand clearance issue. Makes good sense to open 'em up a bit for an engine that is loaded the way a jet (or any boat) loads an engine. And I can understand any warranty issue. I didn't know GM had a warranty on an engine like this.

I had another question about the engine combo...
It's a 4.375 stroke and 4.560 bore for the 572 inches.
Is this better or not than the square 4.5 x 4.5 572 combo that I wanted to build.
Just looking for options here.
Buy it all in one crate or build it myself.
The clearance issues have nothing to do with load. It's all about temps and expansion of components. Hot internal components expanding with heat. Cold block and heads not expanding.

As far as bore and stroke combo I always prefer a bigger bore and shorter stroke for a couple reasons. The rod angle is one, unshrouding the intake valve the other.
 
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