question for engine gurus ! 572 / 620 hp crate engines
 

if you take time to read the description... what is not usable for a marine application? what need to be done to make it reliable in a boat?
Are the parts good? is it only a matter of going bigger clearances ? what else ?

been in my head for so many years...

thanks for your time and input!

Attachment 576796

There was a guy in Europe somewhere that built his own boat and used that engine without any changes internally....just get marine grade starter and distributor...maybe change the carb to a marine spec with the J-tubes etc and it would work........and of course marine exhaust....If you didn't want any problems long term then look at the freeze plugs on the block to see if they are brass...if not then change them out....
Im not aware of anything that was done to open up clearances on the motor...

User 5050 on here used them.

Also, Spectrasonly, i believe was his name, j, helped is buddy in Washington State or somewhere NW (Vancouver ?) with that hand built boat and 572. Was used to bring owner to an island home in cold/wet/rougher waters.
Had extensive right up on the boat, and correcting the CMI exhaust, and etc to make it work.

I’m completely uninformed and inexperienced, but from what I gather GM crate engines do not differ in internals or clearances between street and marine. Replace the freeze plugs, verify the cam is usable for marine, and bolt on all marine accessories. I beat the snot out of a ZZ502 with no issues with the long block itself.

i am impressed ! thanks!

From what I understand, the black engines are untouched by Merc except to add accessories.
The clearances are factory GM. I assume the Merc race engines get a lot more attention.

i could be wrong but didnt ososteve try to put a set in a cigarette hull years back? both seezed as the clearences were to tight for marine raw water setup. maybe with a sealed fresh water cooling system it would be better. i know that merc, ilmor and others get the short blocks from gm, add their intake, exhasut and accessories and sell them but are these fresh water cooled or raw water cooled engines? and they do not make a lot of power either being the black motors.

It was OSO OG founder Jeffrey Cheng, and he put them in his Gladiator.

https://www.offshoreonly.com/forums/...gladiator.html

Do a search on "ZZ572" here on OSO. It's come up a few times.

I had a ZZ502 in a jet boat, great motor.

https://www.offshoreonly.com/forums/...ator-small.jpg

Great info!