Slant Six Dead Spot

Defiantly not a lean condition, it has a Motorcraft off of a 390 with a 460's venturi cluster in it now and it is a bone stock slant. It smokes black when its under throttle.

As much as I would love to get rid of the OSAC valve it is the only thing that has really helped it and made it half way drivable.

ok so then maybe its bogging...

ok so have you done the basics and adjusted the valves, and made sure the timing mark on the balancer is right? they like to spin and move the mark around