Mustang gt carbriator to fuel injection?
Not really. The problem here is that you have a non-roller 1984 5.0L and you want to put it into a Mustang that came with a roller engine originally. The engines aren't exactly the same, notably the block, heads, and intakes, and you can't just put the heads, intake, and fuel injection system from the 1988 back in it using the 1984 bare block. They're not compatible. The 1988 roller engine has to have the heads and intake from a 1988-95 Mustang in order to work and you can't use the heads from the 1988 engine on the 1984 block. The 1988 fuel injection system requires the use of the newer heads and intake. You can't put the 1988 heads and intake on the 1984 block because it isn't a roller block. The lifter bosses are taller in the 1988 block to accommodate roller lifters(all 5.0L Mustangs from 1985-95 had roller engines) and the camshafts won't be compatible either(1984 cam was conventional and 1988 cam was roller). The 1988 heads had roller rockers and were redesigned for the fuel injection system.
You need a 1985-95 engine block which were roller blocks(1985 was carbureted but was still a roller block and 1986 still wasn't the fuel injection engine that the 1987-1995 used but at least the blocks were the same and compatible with the 1988 system). Take a used roller block from a 1986-95 Mustang and use everything off the 1988 engine including the heads and intake and all accessories and do the swap.
My suggestion is sell the 1984 GT if you don't like the older style because a lot of people do. If it's in drivable shape someone will buy it and if it's in good shape someone will pay a good amount for it. If you want to repair the 1988 Mustang then find a used roller block from 1985-95 and use all the parts that bolt onto the 1988 block. Of course it only makes financial sense to do this if the 1988 Mustang is rust free and has relatively low miles. Otherwise, you shouldn't bother.