running twin 454's, looking to upgrade power without losing reliability, considering 502 crate motors, I have been told yes, no, and maybe, any thoughts?

Thanks.

www.1800runsnew I had their 502s and was happy. They also have biggere power available

You can rebuild yours to higher hp's or custom build two. Let me know if you are interested.
Thanks Mike
Roccard Marine Engines
[email protected]
570-956-2840

PM Kidnova, if you are thinking about 502 crate motors...

MUCH more to it than bolting it in, but it can be done.

Kid KNOWS ALL about it!!!
At least with a 502/502 in a boat...

I see this all the time and wonder to myself, "why"? Granted I could see a possible cam swap being required but what else is different. I read somewhere (could not quote the source) that Mercury Marine purchases the long block from the GM truck division before doing whatever it is they do to them to make them marine engines. I can only assume they are installing their own proprietary cam grinds, installing their specific intake and induction system and electronics. If they are doing something more with them someone please enlighten me.

I've heard the same thing and it may be true, at least for the black motors. My crate ZZ502/502 seems real happy under the hatch. Only around 125 hours on it so far, but no known issues. We left the ZZ cam in it too, 110* LSA, seems fine so far.

Also, to date I have'nt heard of any real issues with a ZZ502 being used in a boat.

That said, IMHO if you're gonna take it out and go WFO all the time, or do allot of poker runs, I think some attention to piston cylinder clearences may be in order. But, I guess that would stand for any engine you plan on running hard often.