American Classic sells them:
http://www.americanclassic.com/asp/d...to&exyear=1966
I would imagine Brothers, LMC, etc also carry them.
As for the question on the second clamp, it's been many years since I eliminated the in cab tank, but I believe the stock hose clamps were the double wire type, and could be tightened or loosened with a 1/4" wrench. That was the only way I could reach the upper clamp.