Can I put a 4.6 Triton motor in a 1977 ford f150????????
If so what modifications do i need for the newer style?

Sounds like quite a mountain you are climbing. You are going from a carburator with vacum controls to a fuel injected computer controled machine. The newer Fords have fifth generation Electronic Engine Controlls and you are pre EEC1. Your fuel pump is on the engine, now they are in the fuel tank. You have to add the whole wireing harness for the engine, coil pack and fuse block. I would look on the web to find someone who has done this successfully. Good Luck

If this would not work what fuel injected motor would be compatible with a 1977 ford f150 then?

In 1980 Ford put it's first fuel injected engine in Lincolns, in pickups in 1985. So those early systems might be easier but you can also buy fuel injection aftermarket kits for a lot of engines using throttle body injection. Another problem you've got to figure out is motor mounts, bell housing on the transmission. You may have a C4 or C6 if auto and will be going to a E4OD or 4R80 and if manual tranny it could even be a harder match. People to put any engine in any truck but they have a shop and do their own fabracation and know the electronics part. You can do it but it's not going to be easy.