Vintage tees run small when compared to modern sizes. Although they are generally smaller in size, most vintage shirts we use are tubular or circular knit. The body of a tubular knit shirt has no side seams, resulting in a draping, boxier fit in comparison to modern t-shirts.
If you are trying to decide between sizes, I recommend sizing up.
Marsh is 5'10 and photographed by Katie Flaherty wearing sizes small through extra large.
VINTAGE EXTRA LARGE: