I believe this tank goes on a late 30's Indian Chief that John Bivens was restoring a couple of years ago. It was an once owned by Steve McQueen and what is really cool is that the current owner actually rides it. If my memory serves me correctly, this the second restoration since he owned it !
I was at Bivens shop and saw the bike and remembered a picture in an old Easy Rider magazine of this exact bike when it was sold off from the Steve McQueen auction. I found the magazine on line and gave it to the owner. Kind of cool. By the way John Bivens is a master motorcycle restoration man.