Fuel Vapor Line

Didn't get past removing the vent line from the tank when I dropped my tank.

What does the vent line attach to up in that boxed it area in the bed?

Manual appears to just show it looped?

It comes out of the top of that box in the rear corner by the tail light, then loops back down below the level of the filler neck. On my '65 pickup there was a small u-shaped pipe the hose plugged into going up and then a separate hose plugged into the other side going down.

I never noticed until I took this picture the little metal hanger in the corner (and the rust hiding behind the pillar   )

x2, there is a preformed u-pipe that connects the hose from the tank then goes down and into the frame rail. The hose connection is larger at the tank, iirc, you want to get the hose that fits the 'u' then force it on to the tank connection. The original had a molded end at the tank. The 'u' pipe hangs from a clip hidden in the back corner. You have to run it back that way or you will overflow from the vent when you fill.