Adam4.6

hey guys ill try to make it short. I'm working on swapping a 5.3 with a turbo and 4l80e into a foxbody and currently working out the fueling details. the goal is to have a fuel system that will support in the 600hp range on 93(no e85). I plan to keep the truck intake (it has factory return rails with the regulator built in) and everything is going to be managed by a holley terminator x efi set up.

injectors: are 80lbs. injectors appropriate? should I go any bigger/smaller here?
fuel rails: will the truck rails work for what I'm doing or should they be replaced?
pump: I'm kind of in the dark the most on this one. I'm not sure what size pump would be most appropriate. my initial thoughts are to run a walbro 400 or 450, but I'm open to all suggestions here.
lines: whats an appropriate feed and return size? the car is originally a 4cyl foxbody so I'm making the assumption that it would be in my best interest to just run my own feed and return and not try to make the factory ones work, if im wrong please tell me lol.
regulator: does any one have a particular recommendation? I'm assuming the stock truck regulator isn't going to cut it(if it will that would be great) so how do I go about getting around this?

if any other details are needed please let me know, I tried to add in what I thought was relevant.

thanks!