Chevy use to use manifold vacuum advance and then switch to ported vacuum for smog rules, I don't use vacuum advance on any of my hot street builds, especially with todays electronics EFI set ups work scope
BB Mopars on pump gas seem to like 14 to 18 degrees advance BTDC at or under 1200 RPM and then all the advance in by 1800 RPM, 32 to 36 degrees BTDC total with the correct tune and correct heat range spark plugs wrench scope twocents

Last edited by Cab_Burge; 12/29/23 04:53 AM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)