On my '73, there are the 4 vent lines coming off the tank as well. Problem is, I couldn't find a vented gas cap that fit my filler neck to allow for the venting so I am stuck with the tank vent. There has to be a vent somewhere, or gas won't flow. A '70 or '71 ebody gas cap wouldn't fit; I tried. An alternative would be, so I was told, drilling a vent hole in the gas cap somewhere, but I wasn't so sure that this wouldn't allow spillage or the escape of gas fumes into my garage, when full, so I am back to square one. Another concern that I had, is that if you just run a line somewhere for a vent, is there a chance that spillage, or the smell of gas fumes from that would occur. Maybe some kind of one way valve installed at the end of the vent line, which would allow for venting in, but prevention of spillage out is the way to go. I just haven't figured out what kind of valve, or if there even is a valve out there that could work for that.