[Unionwelder]

Hey guys, I'm swapping my cab tank for a frame style. My question is does the length of the filler neck matter? What I'm planning on doing is running a stainless ep tube from the tank back into the cab from underneath to the original filler cap. (I like the look of the filler on the side of the cab) but want to make sure the length of tube won't effect anything. Vapor problems etc.
Thanks