About 4 years ago or so there was a build that the guy was trying to make that happen, he had drilled a hole in the cab and had mocked up a long length of PVC pipe about 2" diameter from the cab back to the tank. I have not found or read any completion to the guys mock up, cant recall his handle or the build name, he did say the PVC was going to be replaces with different tubing, i would assume something like exhaust pipe..
I did find this in a search, not much help..
http://67-72chevytrucks.com/vboard/s...fill+tube+pipe
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