383 engines need to breathe and really do well if they can turn some RPMs.
Bolt ons, 750 CFM carb, a good solid lift cam, and stronger hardware (rod bolts) with a 3.90 or 4.10 ring and pinion gearset and watch out!
My friend did less than those mods on his Pistol Grip 4 speed 383 70 Roadrunner, but he did go with 4.10 gears and man-oh-man it was a terror on the street!