Ok i'll get the boat aut of the water now is turist season and my boat can't stay if it is not running...newer mind when i get time ill pull of head see what happend..Thank's guys your the best

first pull the valve cover and see if everything looks ok pull the coil wire and crank it over and pay attention to #6 rockers and recheck valve lash

I don't know if only one would contact a piston, but it could create a hot spot for detonation, and that's what it looks like (as SB had said earlier)
Personally, if I pulled a spark plug and it looked like that, I would have pulled the head before it even cooled down.
I've blown a lot of stuff up, and replacing one piston is way better than waiting for it to go out the side of the block at 5000RPM
At the very least the electrode has gone somewhere, if it got pinched in the exhaust valve on the way out, that valve is going to fail as well.

Got the boat aut...No more driving i won't risk engine blow up...When i take apart the head i'll let you know what happend...thank's a lot

Just wanted to say hi to all of you guys i did not work on my engine but when i do i'll let you know...hope you are all good..thank you for ewerything.I try to collect some $ before i take apart my 502..Special thank's to SB

Hey crew..i hope you remember me...your student from europa.Im going to start working on my 502 in a few days...I have to figure out why my spark plug melted but before that a man asked me to check aut a par of big block engines they look fine and work ok..They are edelbrock carbs and since my 502 has a holly i couldn't tell him much..i took picture of the engines maybe you guys know more..how much hp do they have i dont know..are they special or standard..that sort of stuff






I realy hope you remember me...

14015445...454.......78-90...2 or 4 bolt

Mortec Chevy V8 Big Block Casting Numbers

O man...hey speedy thank's for the page i've found that they are 7.4.Nice you remeber me..Are they standard engines..asking because of the polished valve covers and edelbrock writings on the intake

Im sure pretty sure standard with a couple aftermarket bolt ons

EDIT: see if there is a stamping on the block front left pad where the head bolts on

No oem engines came with those valve covers nor intake manifold nor carburetor.