I run non-oxygenated 93 octane pump gas. Combo is a 400 based 452” 3.75 stroke at 10.65:1. Heads are 84cc Source Stealths that have been milled & cc’d at 82cc. Flat-top Iconn pistons are at zero-deck. Cam is a flat-tappet solid, 252* (.050) & .573 lift. (Currently at .610 lift with 1.6 rockers.), on a 109* c/l. I’ve been beating on this low-budget home-built combo for 9 years now, and still finding more in it. A new best was just found this past weekend.