So... pretty shortly after I got my 73 Challenger years ago, I decided to redo the entire fuel system and set it up like a factory 440 six-pack.
Here's what I have:
70-style tank
3/8 sending unit
3/8 fuel line
1/4 return line
Six-pack vapor separator
OK... here's where I think I may have screwed up... I still have my original 73 filler tube which doesn't have a vent line that dumps out at the frame rail.
The car runs good, but DOES have a weird random hiccup / backfire in the carb that I have never been able to get rid of. This may not have anything to do with the tank / fuel line setup... but then again, I suppose it might.
I guess the real question is... even with the return line and vapor separator, do I still need some kind of vent line? What kinds of problems might not having it cause?