Thanks Guys,
Just to clarify, it's the fuselage tank (behind the passengers head) that I was wondering about. My plane doesn't have a fuel pump so I was trying to figure out how it would stay full but I think it was origninaly intended solely as an auxilliary. My question was inspired by the possibility of a leak in it. However, after reading more I find an actual header tank may be required as you suggest. I've got a C-75 with the NAS-3 carb so it would seem this planes been flying on the edge. Oh well, I'll tackle it after I finish it's new paint job.
Thanks again.