Found this 2004 ZZ502 engine for sale. What would it entail to turn this back into a car motor as I have no knowledge of boats? They want $550 for it and say that it has 130 hours running time. Too good to be true? I'm thinking that all costs might be covered in the sale of my rebuilt 396 to do the swap. Considering the cost of this motor brand new the price sent up a red flag.
Thanks.

Well, since the 502 was originally designed for the marine market it is not surprising that you would find one in a boat. A ZZ502 is not the same as an OEM marine 502 - but maybe this was a ZZ502 dropped into a boat. Freshwater or saltwater use? 130 hours is pretty modest - what kind of boat? Have you actually seen the hour meter yourself - or is that the sellers guesstimate? Does the engine actually run, why are they replacing it? At $550 they are selling it for core value, so that tells you what condition it is in.

That engine should bolt right in wherever an engine bay is big block friendly. Many marine 502's have Q-jet carbs, what is on this engine? Depending on the oil pan it has, you may need to get a different oil pan. Oh yeah, there is no fuel pump boss on the 502, so it requires an electric fuel pump.

Good luck, Thomas

Thanks Thomas,

This is the ad: "Motor For Sale!! 2004 ZZ 502/502 Marine Ready Motor with complete header set. 130 hours. Still in the boat, runs great, but I am upgrading to a super charged machine. Serious inquires only please."

Considering the ad is local my best bet would be fresh water.

I only saw the ad right before my post and the wheels started to turn :D.

Go get that sucker, Hell of a deal especially if you can hear it run. I'm guessing it's gone already.

LK

some of the b/b's in boats used a gear drive on the cam, diff cam specs, also i have seen lots of rust in the blocks-a 502/502(if thats what it really is) might be the same as a car engine-most of the "standard boat b/b's" had the small peanut heads, for torque-for the money, it might be a good deal, again, depending on rust(they get a lot of rust around the back of the block, crank flange, etc) you can make an easy 540!

Must be gone...I can't find the ad anymore.

If it's still avalable, here's some other tips:
-you'll want (need) an electrip fuel pump
-all accessories should bolt right up
-a true marine motor had iron heads, and could be ported to get over 600 hp out of them. We built 509 cid/609 hp engines through the dealer, and were selling them for under $9k after all machining and new parts. Since you already have a big-block, you can re-use your intake/carb if they are up to par
-external dimensions should be the same

Lemme' ad a comment or 2. Mercury Marine sold 502's long before Chevy sold em as over the counter crate motors. The first ones were in std Mk IV bowtie blocks and DID have a mechanical fuel pump. They were rated at 440 horsepower had had rectangular port cast iron heads and an alum. intake, similar to an old L78 intake, but with the water passages cast on top of a bronze liner to tolerate salt. They were basically the same block assembly as the 502/502 crate motor with a different camshaft. I haven't seen a gear driven camshaft in a Mercruiser engine in a long time, but they did in fact build some that were reverse rotation. They're very rare and it's doubtfull that it's what this on is, but even if, a camshaft, timing chain and gear set and distributor gear would change it.

If the engine is a Mk IV it'll take the std. old style BB chevy stuff. If it's a MkV it'll require the newer style oil pan since it has a one piece seal and a different set of head gaskets offered by FelPro if you want to run older style heads.

In any case, sound like it's a steal for that kinda money. I bought a couple of warranty 502/440's about 10 years ago (Mk IV's) and paid 1800 each. They make cool 540's too with a rotating assembly change.

Now I know why I couldn't find the ad today. I just found it and they "adjusted" the price -- now $5500! They must have had a ton of phone calls, LOL. What a difference a "0" makes :D!

I saw the ad about 15 minutes after it was posted last night and just stared at the price thinking "$550...???...OMG...for a 502....$550?!?...something HAS to be wrong with it. $550?!?...a 502...better ask some questions PDQ!!!"

Oh well...I bet the sellers are laughing about it, too...now:D!

won't the marine motor spin the other way

For 5500 dollars I would rather just put it toward a brand new crate 502 instead.