I had missed this before, great find on this one. I don't think it's quite as old as you think- I'd personally say mid to late fifties, like 56-58 or so. It seems too much like a middleweight to me to be as early as 1940's. Typically, the ballooner tankers equipped with slim delta lights and thinner tires (the 26x1.75 or lower profile 2.125's) are from the end of the fifties when manufacturers began to head towards middleweights.
I just noticed, too, that you have the later style dropouts that look like Monark dropouts. (They have a funky shape in regard to previous setups; the elongated rack strut screw holes create an ear at the end). Joeymac's bike further down the page is the older, 1940's version of your frame, as it has the more common dropouts (which are more simplistic in shape, and do not have the elongated holes or ears).