I'm running 10.5:1 with 6-7 lbs. I got a 331 chevy using a carb blow-thru setup. The car's got iron heads as well--so i'm nervous that i'm somewhere close to detonation. The blow-thru setup is suppose to cool down the intake charge about 30-50 degrees due to liquid fuel being introduced by the old skool carby. Gotta love that latent heat of vaporization of old technology. I've had the timing set at about 32 degrees total, but recently backed it off closer to 29 to be a little safer. I was told from other people (including vortech tech dept.) that I may be able to run the boost a bit higher at 8psi without a problem. But I'm afraid that'll be pushing the motor to blow a head gasket or rattle my pistons around some. The tuning is old skool as well as the induction and required some fancy playing around with holley jets and screw-in air bleeds. I made it overly rich to help cool down the intake charge further and to help prevent any possible leaning out at higher rpms. Any suggestions as far as upping the boost levels? I would appreciate any opinions!