OK guys, this is the vent/roll over valve that's in the tank top itself:



It's one of the two types that Tanks, Inc supply based on what vehicle the tank is for - the other is one that fits in a fill door or in a fender well and at the end of the vent line. There has always been a little bit of gas odor, but since I put more then a gallon or two in the tank(probably has 6-8 gallons now (14 gallon capacity), it's gotten much worse. Pat, I actually added about a 5' length of tubing, ran it through the frame to the back side of the rear fender and coiled it up behind a fender brace - no help. The next morning, same thing.

Mike, with a Performer carb and Carter mechanical 5-6# output fuel pump, I don't need a return line

This is an early version of the tank plumbing before I went to a 3/8" hard SS gas line. The vent/roll over valve is the brass fitting in the middle. The tubing comes from that valve to a point about an inch or so below the bottom of the tank: