This is what I found.

Head. 440-1

Stock block...

Looks like Detonation effects damage for sure..? Whats the compression and fuel octane combo?

Weld the head, deck block back at it.

That's a good point! I don't know the exact compression as I went from an 88cc chamber to a 72 cc when I put the -1's on it. It was blue printed at 12.9 originally. I was running 116 Sunoco as it was the same price as 114 at the Sonoma pump. I scored a basically free barrell of VP 110. It sure seemed to like the VP fuel better.
I went over the block with a scotch brite wheel and it just has this little etch. I think I'll run it for the last couple races after getting the head fixed. With some better ⛽️!

I had the same thing happen years ago on a set of original 1962/63 max wedge heads on my old bracket car, them dang Perma Toque gaskets melted a deep groove between the #4 and #6 cylinders on the block and heads
I had them both cast iron welded and had to have a shop, Valley Head service, grind both of them flat on their wet surfacing machine
All the other shops I contacted in SO CA back then said they wouldn't attempt to cut the block or the heads on their surfacing machines
You got really lucky on that block

happened to a buddy of mine and then to us. thats why we use victor reintz or cometic. felpros are not good for us. never had another problem with vr or cometics.

Cometic's this time as I had the Felpro's laying around and never had a problem with them. Until now. Yeah Cab, luck has been good to me with this engine. Although I never really ran it after the problem occurred. Just enough to find out it wasn't ignition related. Plugs actually came out first this time and really told the whole story.

Fel-Pros suck!

Cometics here and zero issues!

Fill the groove with JB weld and hand file flat. Get the head fixed. Use something other than Felpro. Run it. When I was burning up Felpro gaskets, I called them. They told me that their perma-torque and race gaskets both hold to a max of 12:1 compression. At the time, I changed over to the orange gaskets from Dvorjak racing out of Florida. Never had a problem again, until I started cracking 915 castings.

I don't know that they actually suck. They went nearly 5 years and won a division championship. I think I was just a little too hard on the beaver Ward. Yes Cometic is a better product.

17059 Fel-pro Marine gaskets forever at just 12.1.1 and even reused em after a Pettis dyno session years ago..........do you run a wide band to verify/compare plug readings too............

No O2's. Dom, do you know what the compression might be if it was 12.9 with an 88cc and changed to a 72cc chamber? Know any mathematicians?

Lots of math guys on here can answer that but I would think it would jump a bunch........you NEED a wb my man...........

Plug your engine specs. into United Machine(KB) on line compression calculator with both size CC and see the results
Probably around 15.+ to 1

Yep, I get 15.6:1

Thanks guys! Wow! That much? Time for Q16...I've been meaning to do it for awhile now, might as well bite the bullet...Piston to valve is better than .120, time for a .027 gasket and way more cam...

If you're going to Q you better have the carb specked and sized for it.............

I don't know how aggressive you are with your Scotch-Brite wheel but ANY removal of material in this area of the deck lessens the torque applied to the gasket in this critical area. Remember that if the issue reoccurs.
Just an FYI for anybody cleaning deck surfaces in general.

Personally I'll choose a razor blade, solvent and a rag to clean the deck surface. If it shines like new.... you removed material. Scotch-Brite has no business around an engine anyway.