Thanks to Brian E. we now have a name for the model I called Big Red. Brian also sent me a few more photos.
That's Harry Seton and it looks like he's wearing Navy pants in two of the photos. Thanks Brian!

A collection of classic male physique photos from the 20th century with an emphasis on the thousands of men who posed for Athletic Model Guild (AMG).

The only name I have for this guy is Big Red. His name is Harry Seton.
I guess he was tall or something.