Ok, started a thread asking about a z010 cam. Well now that I have more time and actually looked at my heads, I am wondering just wtf did I had to begin with???. I bought the boat at the end of 09(first i/o ever and a ford guy to boot) so all I knew was what the seller told me. I was told that it was a factory rebult mercruiser 330hp carbed engine, gen V, with a diesel bravo 1 outdrive. The hull is a 1981 210 Chris Craft Scorpion bowrider??? Is this even correct after the other things the seller told me, lol? The boat itself was/is in fantastic shape and had been restored/rebuilt in Florida. I do know boats/fiberglass/paint/stringers/transoms/etc. So ALL of the hull was checked and found to be in pristine shape. Whether is was foactory or not, who0 knows. Unless Chris Craft painted their hulls, then it has been repainted. The transom and stringers appear to be solid tibers, or at bare minimum, laminated 2x8s or 2x10s. Transom is a full 3" thick(pulled the through hull mufflers to check)

Fast forward to today after blowing up that engine, lol. Here is what I know...

1) out drive is indeed a diesel bravo one with 1.5 ratio(according to the sticker on the outdrive with the serial number and ratio) with a 17p mirage plus prop. The prop lookes older but does have the capped vent holes. I guess you could just say its not "shiney and polished". The outdrive however is pristine and looks mint. I need to get the serial number and see what year it is though
2) original block was a gen v with a flat tappet "z010" cam
3) heads are large oval, adjustable rockers and are casting number 3999241 which comes up as a 1972 head???
4) intake is a gm 4 barrel, dual plane WITH brass inserts on the cooling ports and thermostat housing
5) The entire engine from intake to pan, when I bought the boat was a light yellow color(appeared to be factory, possibly even powder coated on the oil pan, intake, and valve covers.
6) Pistons were forged flat tops(dont have the numbers off of them anymore)
7) crankshaft was forged(dont have numbers on it either)
&
Please help me figure wtf this was. Was it just an engine someone put together, or was it actually something Mercury built?

What is the difference anyway???? You have what you have now anyway. Rebuild it the way you want to.
No Merc engines were factory painted yellow. They were all painted with black on the block and heads from the factory.

A 330 carb has a cast crank and cast pistons from the factory. Don't consider it a 330 anymore, consider it a motor that somebody put together - maybe they did a great job, maybe they didn't, but it is no longer a Merc 330.

Somone pieced the engine together, no big deal. I have Mark IV heads on a Gen V block. What happened to the engine, did you have a failure or just upgrading?