Cam is 254/248 @ 050. 614/620 lift. 110LSA. 106IC.
Intake is super vic and headers are 1-3/4" but I don't think they are tuned length.
So is the reversion something like a resonance at a particular RPM that disrupts air flow or signal to the boosters? How do I tune the carb at a particular PRM only? Surely at WOT and 4K its flat out and well and truly on the main circuit.
Could this be a port match problem, i.e. the intake face may be cut too big in some areas and the head port is interfering with flow? Or would that effect flow more as RPM increases, not in a particular band.
Changing intake or headers is not an expense I want to go to at this stage. What about a spacer or super sucker? Or will that just make the dip happen at a different rpm?
You say big cam overlap can cause this, what about if my lash is 002 too tight - could that cause an increase in duration big enough, or is 2 thou stuff all?