Seems I blew a head gasket. Loosening head bolt I noticed two close to the break in gasket were looser than the others. My set up has 11:1 compression with .039 compressed head gasket. I have cometic but they are .020 and will raise compression to 11.6:1. I have aluminum heads. Will this be an issue with 93 octane. It’s a 318/392 thumper cam. .513 lift intake
