9.5:1 with iron heads, a smallish cam like the 272/.455, and pump gas is about the max I'd run on the street.
Been there, done that, had to pull timing back on a 3400-lb Duster with AT & 3.23s.
Still ran great, but was octane-limited (Calif 91) and would ping with the usual performance timing curve.
Had that cam decades ago in a basically stock 383 RR restoration, ran nice & was pretty close to stock behavior.
Nowadays I'd run a cam with more modern design.