may need more initial timing; which the distributor should be reworked to reduce centrifugal degrees in it. single plane intakes/low vacuum cams/low compression/high overlap aren't a good mix for something your going to drive. power valve in carb may need changed. to me this is the perfect example for not over camming a 383.

just looked at hugh's website. that cam has 21 degrees of overlap at .050". that's nearly identical to the 284/.484 cam. in my opinion, over cammed for 8.5:1 compression 383 and definitely won't run thru stock exhaust manifolds (if they're being used).