holley 750 street h.p. vac. sec.full throttle under load acceleration is great.at idle in park when i hit the throttle fast it stumbles for a bit before picking up.i get fuel as soon as i give it gas,so i assume the pump shot is adjusted correct.not sure if its a shooter issue?timing is 38,vac.advance is not used.i know its a tunning issue,just wondering what i need to play with?shooter size?