I've had a lean tip in off cruise if that's what your talking about, this is with three different carbs and now with the mechanical 6
Pack! I've had timing as hi as 22 initial and as low as 10. Also I know my pump shot is instant and have gone as hi as 38 on a 400hp 360. I've always used the idle vacuum in gear and go 2 under my car pulles 7.5" and I have 5.5 PV in it now. Make sure your timing and pump shot is right. The next thing I may try is a PV 1 or 2" under a light cruise and see if that helps.