Upgrading to 3/8 fuel line
The 4 tank vents that year were designed to go up to the vapor separator tank in the trunk. If you eliminate that, and just hook one or more to a vent of some sort, you may create a "puke" or "siphon" situation. If I were in your shoes I would put a vent line branched into the filler tube like the non CA 70 and the 69/ earlier cars. This was simple and works well.
What is not clear in this diagram is that the vent tube bends up and goes clear up to the top of the quarter panel, then down along the filler tube, through the gasket, and open ends just inside the rear frame rail
The 4 tank vents that year were designed to go up to the vapor separator tank in the trunk. If you eliminate that, and just hook one or more to a vent of some sort, you may create a "puke" or "siphon" situation. If I were in your shoes I would put a vent line branched into the filler tube like the non CA 70 and the 69/ earlier cars. This was simple and works well.
What is not clear in this diagram is that the vent tube bends up and goes clear up to the top of the quarter panel, then down along the filler tube, through the gasket, and open ends just inside the rear frame rail