does anyone know how to swap out a 262 6 cyl to a 351 or 460 in a 1990 f-150 pick-up?

Your best bet would be to find a donor truck because you will need the engine loom and PCM, Exhaust system "Y" pipe and possibly the front engine accessories such as the air pump, alternater, and related brackets. The frame is the same so you won't have to worry about that. A donor truck would save you alot of headaches in part shearching and also you would know how/where they go.

are you going to use fuel injection