"Burnt" spark plugs
 

Went out for a small run yesterday and once i got back i noticed that 2 plugs were burnt. pics below of one burnt and one not burnt. Also, one of the cylinders has no compression now. I think im taking the head of that side to check if the valves are closing correctly.

Any suggestions as to what may have caused this?

The porcelain has a green tint. Green=lean. Tuliped an exhuast valve or a lifted ring land is my guess. Now, why did it go lean in that hole????

it's not good....what is the engine setup ??

Looks like detonation damage, if you really have 0 compression you likely holed a piston.

I am with Ted, Lets hope we are wrong.

Fixx
 

All the above! or blown head gasket between cylinders,if so hopefully it didn't hurt the deck of the block..502???

What cylinders? What year?

Whey you burn a hole in piston you will see metal all over the plug and the plug will look worse than that.
I would also go with blown head gasket.

I had a problem last year with zero compression in one cylinder, it was an exhaust seat. Valve was not closing all the way.

my guess is a head gasket,was there any water in the hole?

don't think a head gasket would burn the end of a plug off like that...

no water in the hole. the pistons are new 4.530, block is a 502 bored to .06

i think that i have a combination of problems, thin head gasket (.03) hot spark plugs and low octane gas.

the oil was clean as well