This came with my old '67 C50, sitting in the bed It had a paper filter in a 60's ish housing on the engine. Thought I would clean it up and maybe use to display it in the garage with a few other oldies. Anyway, being all inquisitive it looks like it was modified at some point with a 3/8th copper tube brazed into the bottom bowel past the filter.Mod for PVC line maybe? Haven't seen this before...Would that be a reasonable conclusion? My memory as a kid working in a real DX service station is kind of dim.