Walt, just to put things in perspective, the source of fuel contamination is at the filler, once it's in your tank you've got a "sealed" system except for airborne moisture ingress through the vent.

That said, with the exception of condensation indicated above, and any deterioration of fuel system components, the "trash" comes with the fuel. Filtering at the tank end of the system, or anywhere upstream is acceptable. I typically mount a spin on type filter near the tank (Ford OE item, Fram also makes a similar unit that has a cartridge in a can). One hint, if you see a tanker truck dropping fuel at your station of choice DON"T STOP. Come back later. The dropping of fuel from the transport will stir up all the tank "bottoms", which contain particles, rust, and water. A half hour later most of that stuff will settle out.

BTW, like the Unis..............is that a '50's track car, or modeled after one?