I run 10psi on my Viper (think 360engine with W6 heads plus 25% extra cylinders). My 9-1 FORGED racing pistons, cam, headers, ported heads, custom intake, larger TBs, etc etc, makes 720rwhp with water/methanol injection. It also makes over 800rwtq soon after 2,000rpm. This is a Kenny Bell TS...