Blown head gasket

hwy2 said

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

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My 367 has run at up to; 11.3Scr/9.2Dcr/190psi with alloy heads, @.032Quench. I run a 2-stage timing curve; 12>14@ Idle, going to 28*@2800, then 32/34 by about 3400. This allows me to run 87E10 full-time. I run the 039 FelPros, with ARP bolts torqued to 105 in stages, on the ARP grease, with no retorque. In ~2005, I replaced the cam, redecked the block, and subsequently the Scr changed to 10.95, the Dcr to 8.9, and the pressure to ~185.
Your results may vary.

BTW
This change was deliberate. I gave up top-end power to gain bottom-end torque for my 4-speed/3.55s combo..