My buddy is trying to find some 15" wheels for his '40 that has 5 on 4 1/2 bolt circle all the way around. He like myself doesn't like the steelies without the vents in the center. I have heard that I-H used the small bolt circle and had a wheel that would accept a 40 Ford hub cap and I even have one, but it is a 16. My question is what I-H came with this wheel in 15" ? Anybody got some for sale?
Not sure if this will help but I just sold a '41 IH K1 and small pattern Ford wheels would fit it. I used a Ranger wheel as a spare. The '41-'48 IH probably used a 16" wheel like you say but maybe the '50's IH would work.