ok, was working on my 73 today (shackle flip to remove PO's stacked blocks... ) and when i dropped the tank i was confused as hell to find 4 connections coming out of the sending unit... Pic: http://community.webshots.com/photo/221327895/415335227HnbTeo# and thanks to the PO, everything was creatively replumbed for me so anyways heres what i could figure out: ~1/2" OD (far right) = Gas Filler Vent Line ~1/4" OD (center w/ hose) = Supply Line ~3/16" OD (center w/0 hose) = ??? ~1/8" OD (far left) = ??? So, one is the return line, i'm thinking the 3/16" OD one... but what is the other one for? Another vent? this is on a 73... and as far as I could tell no one had ever dropped the tank before, just played with the plumbing forward of the tank. Anyone know about this?