I just put a 57 b intake and holley 390 cfm on my  55 with a stock 292 and A/T It had A intake with a 4v teapot before/ it sure rans alot better but I have a small stumble when I take off / so far I have check the float level,accelerator pump arm adj,move the pump cam to the #2 postion Im starting to think that maybe I need to replace the pump shooter which is a .25 but Im not sure which way to go. how can I tell if Im too rich or runing to lean? both can cause a stumble or do I need to change my pump cam? Also when my secondary open I feel a kick which I think is a flat spot I think a stiffer spring on the secondary will take care of that problem The cars has 20 lbs vac at idle, I have try runing the timing at 6 and 12 %  with total adv of 38% at 4k also the distributor was update a year ago and it also has a new fuel pump Im hope that someone has has had this same problem and can tell me what fix it