I am doing 5.3 swap into my 1994 c1500 w/t that had the old 4.3. I removed the bed to upgrade the fuel pump to a 96 fuel pump. In doing so I see corrosion on the top of the sending unit. Don't know what to do here. Buy a sending unit of a 96 that includes the pump? Or get a 98 and newer which is a different style? Does that design have a returnless feature? Should i get one for the new motor which is a 5.3 that Is an '02. Any mods to the tank? I would like to keep it as close to factory and really trying not to mod the tank. Modding the harness, I am ok with. Please fill me in, thanks