Ok, changed jets up and down, no change. Changed secondary springs to brown and black, everything the same. If I adjust timing, if I advance, problem moves up higher in the rpm range, if I retard it comes down. I have 2 mallory unilite distributor's, both have the same effect. !@#!@$! Fuel supply is a new holley blue with regulator, guage checks right at 6 PSI.

If the car has no load it seems to rev and fall evenly. As soon as you mash the gas, engine gets to about 2400 rpm and sounds like its going to die, clears up a little and then does it more for about another 5-8 rpm, smooths out then does it again. If I part throttle, the response is quick, and moves right along.

Seems like it isn't carb related although I haven't tried putting another (smaller) carb on it, or technically the distributor either since I replaced it and it does the same thing. At this point my friend suggested it may be a loose rocker or 2 (they are pedestal mount, but I have not checked them since we installed motor and I have put 100 or so miles on it...) Tomorrow I plan on checking them (can't hurt)

Any other idea's? Could it be a carb accellerator pump issue? I have multiple cams, the factory green is on there now...