350 TPI Vortec.....Fuel pressure before start is about 20lbs, after start(while running)with vaccum connected to regulator is about 38lbs...Recently changed the fuel filter. Now the problem is this while driving it the car will drive fine with about1/4 of the throttle depressed, but when I go to give it full throttle it hesitates for a few seconds, then suddenly feels alright and then goes back to hesitating again, Ive searched and searched but could not find anyone with a similar problem. Do my fuel pressure numbers look right? I was concerned with the key on/enging off fuel pressure. Any help would be greatly appreciated...thanks!!

 

Is this vortec running a TBI induction on it? Your info suggests otherwise. If so what chip work have you done?

 

you should look in the TPI section they may help you out better since this is a TBI