He's putting it on a 351 lower manifold is different as well as the distributor. Mustang 5.0 stuff will not "bolt up" There are adapters available to mount the Mustang upper to a truck lower.
Other then needing an adaptor and a truck lower, the rest of the mustang EFI manifold stuff will work. When you get the truck lower, get the truck distributor as well. Drop the siginature PIP wheel off the mustang distributor into the truck distributor and you have all the hard parts. Some fuel line here and there, fuel pump, etc. and you have a much more adaptable EFI then the GM based speed density TBI.
The Ford mass air is very tolerant of not being on the right engine. Since it actually measures the amount of air entering the engine and adds fuel based on the amount of air it does a better job of getting the air/fuel correct. The speed density likes being on the correct engine a lot more. It looks at RPM and manifold pressure, Looks at programming for the original engine for how much air is actually entering, then ads fuel to match. That programming is a lot more then just cubic inches, it includes the flow charistics of the heads and cam. Stuff that doesn't carry over from one engine to a completely different engine.