FWIW, I pulled a tank, sending unit and all fuel lines from a 1990 K5. A TPI pump fits in the TBI sending unit, but makes the higher pressure. I used all ('90) factory fuel lines up to the front springs. For the last section, I had lines made with fittings to match my fuel rails and and the factory lines. These reach from the frame up to the intake. I took the fittings from old fuel lines and had a hydraulic shop do flares and crimps or whatever they do for their high pressure lines. Since they are all flexible (with stainless braid) routing them is simple. Making something with flex/hard/flex seemed too complicated and would drive the cost up, but if you had two sets of lines, each with the fittings you needed at one end, they could probably be joined together for a solution.