Guesses on What happned to the 460?

[Squirtin Thunder]

no jet in the boat piece off junk wont even float
I have a Sanger Super Jet Here that can be for sale !!!

[Captain no fun]

A couple of things are likely;
If you are running OT exhaust with a high overlap cam, shortly after decelleration, you get reversion, you pull a small amount of water into your cumbustion chamber, hence the roughened idle. This cools your exhaust valves to rapidly, into a martinistic state, and over a period of time the valve crystalizes, and can no longer take the constant slamming into the seat. It fatigues, and breaks off.
You could be running older heads, that are not designed to run on unleaded fuel. The exhaust stem has no lubrication, it expands, friction increases in the guide, the friction overcomes the springs ability to pull the valve back into position, and the piston hits the valve, bending it over, and the second hit breaks it off.
You could have weak valve springs. The bent push rod tells of a severe mechanical interference, so when the piston was coming up, the valve was attempting to open. I'd say the problem is in the guide interference from your description.
The water in the oil can be explained from the compromise in the integrety of either a cylinder wall, or head. Look around the forensics of failure analysis is exciting, and will make you a more informed hot rodder!

[Rampager]

What kind of pistons and comp ratio are you running?
Had a nearly identical failure in my 460 2 summers ago. The top of the piston broke thru the ringlands and broke off the tip of a valve which banged around and eventually stuck into the piston top and stopped the motor. I was running too high a comp ratio for hypereutectic pistons. We fixed that all up and replaced just one piston. The next summer the motor started knocking. ran it onto the trailer but on teardown found nearly every piston either cracked or already broken. Was extremely lucky both times no other hard parts broke. (I did bend the rod the first time) At this stage we figured the hypers may last a season at the comp I was running but no more. I went forged at that stage...it was about 10.7:1, manufacturer was shocked it lasted even that long and said no more than maybe 9.5:1 #shrugs#
Good luck, it sucks blowing a motor

[wrenchdogg]

sounds like you guts need to get a chevy .. :rollside: just kidding

[lucky]

i WAS GOING TO SUGGEST - CRYSTALIZED VALVE STEAMS AS I HAVE BEEN READING ALOT OF THAT ON THESE BOARDS LATLEY

[SmokinLowriderSS]

There's my bet for the failure, the valve broke at the stem, and became FOD (Foreign Object Debris ( I been working on aircraft way yyy to many years )) this earned you a busted piston, bent rod, broken rod (all likely pretty much in that order) and a rapidly stopped 460.
I wonder about the bent pushrod, there may have been a guide problem. I don't have any really good guesses to dispute it with.
I'm gonna go about 50/50 on the head because, while the valve can tear up a bunch of stuff, so can that rod jamming in the sleeve. either could have opened a crack to the water jacket. From the amount of water (2 gal) I'm gonna lean on the block. There wouldn't be that much available from a head just on gravity available I don't think. A pressurized auto system would be different.

[Mighty Thor]

here is what It looked like when I took the engine apart.
http://www2.***boat.com/image_center...Broken460b.jpg
http://www2.***boat.com/image_center...Broken460a.jpg http://www2.***boat.com/image_center...1Broken460.jpg
Looks like I will be searching for a new block. This motor was an automobile engine that someone had hung the boat stuff on. only performance stuff here was the performer intake and Marine carb. Probably a combo of old heads, automotive cam and who knows how many miles.

[Jeanyus]

That looks like the inside of the only Big Block Ford that I owned.
Go BBC and use your boat.