The engine is a 71 455 with a Q-jet carb and HEI ignition. When I put the pedal to the metal it's seems the engine floods out then catchs on. The engine kind of stalls even a backfire then keeps on running. I can't get a good start of the line because of the hesitation. o No: Does this sound like a carb problem? Thanks
More likely goes dead lean, pops, then gets fuel, rather than flooding. Sounds like classic symptoms of dead accelerator pump.
The classic lean bog appears appropriate here. Check the following: accelerator pump, sticking power piston, and the dreaded air valve problems, including the possibility of the valve opening too quickly, the accel orifices in the air horn not feeding, or the air valve not properly operating. One other thing to consider here. The Qjet was originally metered for the hot air coming from the original emission air cleaner. If this has been eliminated, the additional air density will require additional fuel, most likely from the accelerator pump. Food for thought.
