Is my fuel pump man enough???

[eightbanger]

Today from a rolling start of about 20mph I floored the go pedal, the kick down came in, the 454 sprang to life and away we went. I could only have reached about 60? hell the trans had only started climbing through the gears when the engine ran out of steam and started spluttering and the power dropped off sharply. I pumped the gas pedal and it would pick up and die off again the whole thing felt exactly like I had ran out of Gas, as the revs dropped and the truck slowed down she picked up again and I drove home. This has happened a couple of times before but I've been lazy about posting the question, is it possible that my mechanical fuel pump is unable to supply enough gas in these circumstances...ie heavy righ foot

Thanks.