If you haven't degree the cam that is in the motor do that first, if it is ground on a 106 LSA and is installed at 107 or more on the intake lobe advance it to 101 to 103 intake lobe center and see how your current parts like that twocents scope
SB with the stock short stroke don't have much bottom end so you have to correct that first twocents scope
What does are car 60 ft. times now?

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)