Fuel return line?

the only lines i have coming out of my pressure regulator, are to the carb, and one to the nitrous system. i have NEVER had a return line on my street strip dart, that was clear back to a 318 with an engine driven pump, all the way to the 408 thats in it now with a mallory 140 feeding it. granted i never set out for road trips in it, but i've never had an issue. however my old 1986 chevy truck see's hour+ trips sometimes, and it has a little electric fuel pump regulated to 6 psi, again no return. it's bone stock and kept eating fuel pumps, so it got an electric pump, a regulator, no return line, and has been happy ever since.

the science between churning up the fuel and heating it makes sense with no return, but with the above gas hogs, i doubt the fuel stays in the lines long enough to matter.