502/502
 

I have the oppurtunity to make a purchase on a GM crate motor (502/502). I'm wondering how good of a marine motor this would make right out of the crate.

Would I have to make any changes (cam, headwork etc)?

I'm getting a real good deal on it so if changes would have to be made I think it would be worthwhile.

Joe K.

Check out www.1800runsnew.com . They have marine crate motors up to 585 hp. Do not use a car motor in a boat!!!!

Teague on tech covered this some months ago. All the wrong parts in zz's pistons,cam,no inconel valves,wrong valve springs etc.

Yea, What Birddog said! I think it was the Oct or Dec issue of PowerBoat in "Teague on Tech". He talked about the ZZ502 and it's marine ability. Check it out.
Eric

I have a pair of these engines, and have had good luck, BUT, you need to make changes. Roller rockers, Inconel exhaust valves, marine cam and marine carb. You also have to know what you're doing when you set up the oiling system with remote filter and cooler. Depending on your existing motor mounts, the eight quart pan that comes with the engine may not clear the mounts. If you are replacing a Mark IV engine you need an electric fuel pump.

"Really good deal" should mean having $1500 - 2000 left in the budget to do these changes. The compression is OK with premium gas, especially if you step up to more cam, but then you better have good exhaust with the water introduced way down the pipe.

You can also buy the Short block of a ZZ502 and add heads. Then you could add what ever heads you want. You could also buy the Accel fuel injection system with the thier intake.You can get a short block for about $4k. This is what merc. uses for the Hp500 bottom end but they run a diff. Cam.


Pyle

are the 1800runsnew engines crate motors? Or rebiult crate motors built to marine specs? Or do tehy take new crate motors and marinize them?

I ahve always heard fgood thing abotu thier engines and people here have had luck with them nust not sure exactly what they are.

They are marine crate motors. I have 2 502's with prochargers and they run great!

The engine is out of a truck and has only 600 miles on it. The engine already has roller rockers. I have a marine carb that I would be putting on it and already have an electric fuel pump. I also have a oil pan that will work. The engine would be purchased for 3700.00. Biggest concern would be the effects of reversion with the stock cam (I've heard bad things). I have a set of Gil exhaust with 6inch risers.

I will surely look back to the article on this engine and find out what I can.

Thanks for all the info.

Joe

Just read the article in Powerboat. I may think about rebuilding my 454 mag instead. Could probably get better results putting the 3700.00 into it.

Thanks Again,

Joe