A lot goes into this but with my car doing 1.25-1.27 sixty foot times I'm set at 1.055-1.065 but everyone car, tire size, and suspension is different. Test n tune is your friend for getting it zero'd in.

1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27

Livin and lovin life one day at a time