Ted G

Sure looks to me like it may have been the head gasket failed first. If the piston had melted down first it should not have run long enough to burn away that stainless gasket material like it did, but if the gasket gave way first the lean charge near the failure would be more than adequate to melt down the piston. And since that is an MLS gasket, if the head and block surfaces were not surfaced correctly, the gasket will fail. Those a re great gaskets but they are not tolerant of any low spots or an RA of greater than 50. And those gasket surfaces look rougher than 50 to me, (but I am not a machinist).

TomZ

Kevin,

I just gotta say that you've got a great attitude towards all of this. I'm sure you're pretty upset about the whole thing, and given the circumstances I would be too. Rather than crying about it, you seem ready to get into it and make everything right. Hat's off to you! And good luck with it. Definitely a nice boat.

-Tom

Budman II

Kevin, you might want to consider just finding a stock 454 to drop in it so that you can get it running quickly and salvage the summer boating season. Then this fall you can start planning a rebuild of this motor, or go hunting for a really nice take-out. You don't want to put a bunch of pressure on yourself to get it done quickly so you can get out on the water. you can probably recoup a lot of the investment on the stock motor when the time comes, or just keep it around as a spare. Don't know what your budget is like (hopefully better than mine!), but many bad decisions are made when we get emotional and hear the water calling us. Winter is the time for building motors - summer is the time to go boating and enjoy the fruits of your labor! Good luck, and keep searching this forum for info, or feel free to ask us and learn.

TomZ

^^^

what he said!!

BajaKevin

This is my first high performance boat but not my first boat....I've learned real quick what's involved with tinkering with boats. Getting pissed off and angry used to be the route I'd take but I've learned it accomplishes nothing. The damage is done and there is nothing I can do about it. The person I bought it from won't make it right so why get mad? Instead just get back in there and get it fixed.

Oh I definitely do not plan to rush anything. I am still weighing my different options but a stock engine is definitely one of my options to salvage some of the season.

dereknkathy

if block is ok, buy another piston and put it back together. what heads? they are open chambers so motor is only 8 to 1 comp. i will betcha he put in too wild a cam to make up for too mild everything else he was calling 575 hp. those are decent dry to tip exhausts though. a 454 mag cam and L29 heads will make a decent 55 mph in that hull cheap get-you-thru-the season package. nothing fancy or pricey.

MILD THUNDER

Those look like Merlin heads to me.

MILD THUNDER

That doesnt look like an MLS gasket to me.

MLS stands for MULTI LAYER. I see one layer.

Thats a normal composition type gasket.

TomZ

There's a 465 HP 502 (HP 500) and a 454 long block in the Swap Shop. I wouldn't even screw with that hypercracked motor. It's done.

The HP 500 is 4500.

If the heads are good on the 468 (probably need surfacing after burning it up), even a "Runs New" short block would be better than dealing with that POS (sorry) 468.

billy boats

Looks like the head gasket went first, most likely because you were torque loading the engine( 4700 rpm max) when the engine started to miss fire that was due to the gasket letting go. Now you run it for 30 minutes at cruise that's what damaged the piston.
Usually when a ring land lets go from detonation it is in the area of the valve relief . Lesson to be learned , if it's not running correctly shut it off before further damage is done.
Sorry you had to learn the hard way, best of luck