chevelle-guy

Just curious, I see a lot of talk about 502's here. I have a ZZ502 I am putting in my car, with stock aluminum heads, 9.5CR, and a fairly mild 224/234 cam. The info packet says to not use them for marine applications. Is that because of the aluminum heads? My MasterCraft has an aluminum headed LT-1 with sea water cooling, and they specifically say you can't take them in salt water cuz at elevated temperatures, the salt water will eat the heads. Does anyone actually use ZZ502's and figure that the heads won't disolve for a million years, so it doesn't matter anyway?

Rookie

iTrader: (4)

Yes, there are a few threads on how some ZZ502's have been turned into Marine 502's. Cam change, remove the 11lb oil relief valve on the bottom of the filter pad and plug or replace with a 30lb. A lot of people use aluminum heads, just flush good. I have a friend that used a base ZZ502 and made I think a 557 out of it. Same heads, diff cam.

chevelle-guy

If y'all don't mind me propagating this thread (cuz I think it's interesting).... What doesn't work on the original cam? It's pretty tame by muscle car standards. It seems like it wold pull pretty strongly off the bottom end while still having some revs for speed. Everyone in the car forum I frequent thinks I'm a sissy for not putting something more wild in the ZZ.

The LT-1 (1994) in my MasterCraft ski boat is box stock mechanically, no magic grind cams, milled heads, nothing. It does use a Cadillac Northstar ignition, which is kinda fun.

BY U BOY

I run the ZZ502 heads and cam in my 454 and have had no issues with reversion or corrosion with the heads in salt. I flush for 10 mins everytime even if I run in fresh water.

ROTAX454

Change the oil pan and replace the carb with an HP4150-950 w/mechanical secondaries. You can do more, but with these and the above basic changes, a solid 500 c.i. marine platform.

Fenderjack

iTrader: (2)

Also might want to put brass freeze plugs in the block unless it has them, make sure your running full dry pipes, so you do not get reversion.. As long as you flush the motor out good every time or in between you should be fine.. it doesn't know what its in. Only thing with a cam is one is made to have power to work with the weight of a boat in certain rpms, one with a car.. That cam prob wouldn't do all that bad depending on what boat it it went it.

John jr

ROTAX454

One of the reasons that this crate motor (with a few changes) is a good marine package, is the fact that it does come with brass freeze plugs in the block.

One of the items that should be on your "to do" list is removing the stamped rocker arms and replacing them with some quality roller rocker arms.

Question: Instead of changing out the valve covers for the taller and angled marine style valve covers, could you use a valve cover height spacer? Or would the marine exhaust clearance be an issue? Depending upon which exhaust is used?

I do have (2) pairs of new Teague polished (and Zoop sealed ) valve covers with the tall polished breathers for sale. I went another direction with my valve covers needs.

bajabob

there is a guy on this site put a gm 572 in his boat it had 300hours and is still running good

ROTAX454

Eliminator build a project boat for a customer using a pair of GMPP ZZ572 (92 octane version) with sucess. I will put together a list of items w/part numbers on the changes those who have used in the ZZ502 for a marine application. Call it a checklist of things to do----in the order of importance. Besides the oil bypass valve, I feel the oil pan is the second most important item.

ROTAX454

This is a Teague cat pan, but any good marine performance oil pan will do.