[HO455]

I picked up one of the later year Suburban fuel tank vent tubes for my 67. I want to get away from the non-vented fuel caps that always seem to leak on hard left hand turns with more than 1/2 a tank of fuel.

One of the things I need is measurements as to where the factory installed them. I'd hate to drill a hole and find something in the way inside the rear quarter panel. The measurement can be inside the cab or underneath where the lines exit or in a perfect world both.

My other dilemma is identifying the 3 lines. At some point in the past I found a thread identifying the 3 lines in the bottom of the tube but dang me if I can find it now.

If memory serves me one line ends to near the top of the tube. One line ends midway up the tube and the last one ends at the very bottom of the tube.
I'm sure the one at the top of the tube would go to the vent canister
The other two I think go back to the fuel tank?

I really only need the one at the top the canister and one on the bottom of the tube. I could fill the tube with water to identify the heights of the lines inside the tube but, I'm hoping someone here will have the information I need and save me some steps.

The factory chassis manual shows the bottom line ( Line to the farthest right in photo) going to the canister but no information about if that is the highest line in the tube.

Thanks in advance.