318 running with low power - dyno

I have personally ran 8:90s in the 1/8th mile with a 318, cheap stock rebuild of a 74 model engine, but with a iron 4 barrel intake with a thermoquad, and a racer brown, .430 lift cam. In a 70 duster street car with a 3:21 OPEN rear on street tires. So yeah, something is off in your combo