i have a 1968 gs 350 that recently was redecked to correct some bad engine work. doing this moved the compression ratio from 10.5 to about 12.5 and have now started putting out head gaskets.i was using felpro perma torque but they are only rated to 10.5. I'm looking for any info on other head gaskets available. I checked out mls gaskets but no one has done one for this motor yet and I would have to pay about $3000 to have them cut the first die. I'm thinking about trying copper but really didn't want to ring the motor. i understand there are companies that make a copper with the fire ring in it but haven't found that company yet.any info would be greatly appreciated. '68 block ,72 heads bowl ported.40 over ross pistons.ta roller rockers and valves .ta intake ,quad carb.car has run 12.60 in the 1/4 at 108.Looking for about a .040 thickness.