I have a 84 F 150 4 by 4 has been redone got a mild cam in it it starts up fine and idles and everything but whenever you take off it's pretty much the falls on his face I don't know if it's the gas problem or electrical and see if anybody else has that problem even when you're driving down the road it runs good then it just falls on his face and runs like crap

 

Not knowing exactly what you have,
Some things you might want to verify,
Starting at the ign sw consider hooking up a test lite or volt meter to the negative side of the coil and watch for any loss of power either visual with the lite or meter when the problem occurs.
If no quirks are seen then you might go after the fuel system, carburetor, fuel supply system. Again don't know what else has been altered , but if possible you might tap into the line to the carb and observe the fuel press for any sudden drops.

This may not apply, but make sure the intake is not restricted like small air cleaner.