hesitation when secondaries open
Couldn't find any threads that dealt with the issue I am having and wondering if anyone could shed some light on where I should go next. I have a sbc 355 with sportsman heads, rpm air gap intake, 650cfm thunder edelbrock carb, comp cam hyd flat tappit cam, msd dist/box/coil. My issue is when I get into the throttle and feel it hit the secondaries off the start, it hesitates quite dramatically then takes off. I initially thought it was my accelerator pump not giving a big enough shot of fuel, so adjusted it....no difference. Tried going to a series of different springs on the weights in the distributor as well as running with and without the vacuum advance....no difference. Tried adjusting timing both directions....no difference. Checked for vacuum leaks around the carb...nothing. The only thing that keeps nagging me in the back of my mind is when i first put the fresh engine in a few weeks ago, my son decided he wanted to hear it run.....cranked and cranked on it....finally got it running and left it idle for about 5 minutes!!!! Both things a big no-no for breaking in a flat tappit cam i am told. Could that be my issue? Have seen no filings in either the oil or filter which has been changed 3 times since subsequent break-in and 400 miles.