Re: Identify this part
that is a bosch pump, possibly the 044 if your truck is making good power. the 044 can support around 700hp, and is like 400 bucks IIRC. its probably too poor condition to read the numbers on the side of it to see what model it is.
those model pumps can be installed inline or in the tank. If your truck isnt making over 500hp I would just take it and its associated wiring out and just put a walbro 255 inside the tank. running multiple pumps is risky business if you dont really need it, because if one pump dies the car will still run but the pressure curve will change and throw off the tune and you wont know the difference until there is a problem.
looking at the corrosion on it, i wonder if that damn thing is even working. start the engine on the truck and see if you can hear a humming from that thing.