According to Cometic, anything less than following their instructions explicitly, is "getting lucky." Or not....
Or just not making enough H.P. to matter.
Guys are making 1000 HP with those gaskets, others are having failures at 350...
If you call Cometic, and send pics, they will tell you what I just did.
I know I'm not smarter than them, so I called and talked to their tech dept before purchasing their product for the first time. I took their advice, and machined as per their instructions, and have never had a failure with their headgaskets. I build blower, turbo, high compression, and Prochargered engines, car, boat and Harley, with no failures. Mebbie I'm just lucky.
But then again, their Buick V-6 rocker gaskets are too hard to seal to the roughness of the head casting and don't fit correctly. The gasket O.D. is too large to fit inside of the rocker cover flange, and the alignment tabs are also too wide. We have discussed that too. I'll see what happens with that...
TIMINATOR