I stole the idea from John, who did a much better job on his truck.
The tank is about an inch too high. I am going to add spacers to drop it down another inch for a better fall angle of the filler tube.
The filler setup is from a marine shop- all coast guard approved for safety. I bought the fill top [stainless], four feet of approved marine rubber hose, and some clamps. It took three hours to figure out how to improve the fir to the tank connection- then my eyes finally landed on a bicycle inner tube- the local bicycle shop told me that the inner tubes are impervious to gasoline so that worked real well and made a good, tight fit. I also used two clamps on that connection because you have to pull the tank to get at it and it is hard to muscle the tank back into position by yourself.
The PO had done a very bad job of setting the fill up behind the marker light. I have seen some nice jobs, but this one wasn't. There was actually a gooseneck in the filler from the poor design and implementation. They hacked the bed up pretty badly, too.
So I re-routed and replaced the old setup with the hose, and it now has no low spot and will fill on its own on the slow speed at the pumps.
I ran the main hose and two vents with smaller hose from the tank all the way up to the filler cap. I took the tube to an exhaust shop and had them weld a small-hose nipple just below the bed. The second tube is capped with a dirt-bike breather that can blow air but not suck it.
I had a friend bend me up a cover to hide the whole thing. It is hinged, held shut extremely well by a big old speaker magnet. I trimmed it with vinyl door edging from the local parts house. I painted it to match the truck and folks don't seem to even notice it. There is room behind the cover for jumper cables, too.
It looks and works 10 times better and safer that the PO butcher job. I love these old Chevy trucks and it is painful to see what happens to some of them.
I have more pics of the before, during aand after but they are all way too big for the forums. I am going to do a truck page on both my knife sites, but haven't gotten to that yet.
The folks on this forum have some GREAT ideas and some unconventional ways of implementing them and they are first-rate.
This is my daily drive year-round so if it takes more than two days it will have to wait 3 more years until I retire
Hope that was some help- if it still isn't clear I will try again.
Thanks,