Are the ends of any valves broken off?

No, no visible damage to the heads at all. They are being gone through now so I will find out for sure if they suffered any damage when the shop calls.

Piston tops should say it all...... See if they are steam cleaned man....

The pistons that the rods broke actually do look a little cleaner than the rest. And I would assume the cylinders that I would call the center of the engine would get water first if it was sucking back through the exhaust as they are directly in line with the riser.

I could be wrong, still trying to figure this out to make sure it never happens again!

Yep, #6 definitely looks steam cleaned to me, and 3 and 5 are suspect too.

Any reason you are running a 6-quart pan on there instead of an 8 or 10? That is one thing I would change for the next motor, assuming you have room.

Yes, the reason is that the person I got the boat from said they marineized 2 zz502's but really what they did was put 2 100% car engines in a boat. Proper oil pans are in the works!

The absence of carbon deposits on the perimeter of the piston tops says detonation. When you take the pistons out I think you'll find the top ring land tried to lift.

And what causes detonation?

Anyone think it started misfiring and the dead hole caused it to suck water back in? Usually happens with a valve issue but maybe the bad skip was causing it to pull water? I also agree that lowering the idle to 750 is better for bravos worse for reversion