273 Commando - Coolant leak - Cometic MLS Head Gasket

The pistons are from RaceTec, Huntington Beach, Ca. They are sweet but pretty expensive. Unfortunately they missed to widen the Pin Boss, so the original rods did not have enough space. Decided to machine them here in Switzerland, instead of shipping back to U.S. (freight cost vs. machine costs). I ordered many engine parts at FBO in Oregon. Don does a good job!

So I guess we circle the problem. I have a nice New Mexican Oil-Stone and will smoothen the surface of the head and block and put a little spray on, although Cometic does not recommend that. I don't mind. Asked them, but they do not provide thicker sealant-coating. Maybe I'll check the bolts (stretching issue) as well. Found some new bolts at ARP.

Any other gasket manufacturer known, that provides thicker gaskets with f.e. compound material?

Engine wants to go back into the car finally...and I promised my mother-in-law a ride with the fish long time ago. :)

Thanks for your helpful comments so far!
Robert