I rebuilt my carb last thursday, Motorcraft 2150 sitting on a 351m in a 1981 Bronco, it went smoothly except the "Power Valve" wont fit. The kit was NEIHOFF, 50$ , and the valve is to long for the cover to fit back over it. Is there a way I can buy a deeper cover for this new valve or will it even work? Thanks for the help.
Your kit came with a two-stage power valve and your carb needs a single-stage unit. The two-stage valves are longer on the bottom.
You can scavenge a bigger power valve cover from a junkyard carb, or raise heck with the store that sold you the kit. You might not get very far with the store because the kits have those lovely warning notices that once you open the parts bag, they wont take the kit back.
Another alternative is to get just a power valve. You can still get them from Ford dealers as a Motorcraft part. You might be able to get them from a chain parts store too, but the only one I've had any luck with on parts like that is NAPA.
To get the right valve, you need to figure out what vacuum the valve should open at. If the old valve is not broken, you can put a vacuum on the diaphragm with a vacuum guage attached and see where it closes.
Check out this page for Motorcraft part numbers for power valves: