stock brake drum size on 3/4 ton 58 Apache

[jayft8]

Hello to all- brand new member here.

first a little background:
I am the recent fortunate recipient of my grandfather's old 1958 3/4 ton Apache - all original.
I am in TX, the pickup is in ALabama and has been sitting many years. Naturally the tires are all flat and rotted.
I plan to go out to retrieve the Old Man this fall.
What I want to do is go there prepared with a spare set of wheels ready with adequate tires so I can trailer up and out as smoothly as possible.
I've got a line on a set of 15 X 7; 8 lug on 6.5 wheels that are fairly cheap. My concern would be in the fitment issue with potential for interference from the brake drum and a 15" wheel. I wouldn't worry too much about a 15" rim on anything built fairly recently; but automotive/part design has changed a lot since the 50s. I would be afraid to discover a 16" wheel is a minimum requirement.

Which finally brings me to my question:
Anyone out there able to give me front and rear OEM brake drum diameters for a 1958 3/4 ton?
Or from experience can anyone tell me that a 15" wheel will fit without any problems?

I'm reading through the forum and see that a lot of the projects are updating suspension and drivetrains, but if there's anyone that can talk to me about stock OEM; I'd really appreciate any assistance one can provide.

thanks

JT