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Any Ford wheel from at least1973 to 1996 will fit on the bronco. The lug pattern is 5 on 5.5 so wheels are easy to find. I run 31x10.50s on by stock bronco (92) so I know they'll fit.
Some Scout ,jeep (to mid 80's )dodge (if center hole is big enough) Will bolt on and I have used them all on trucks from 76-96. Most latter jeeps were almost identical to 80+ ford rally in looks except center cap. Most 80's dodge rims seemed weak and rust prone. But If you get after market rims they will be Ford, Dodge , And jeep bolt pattern.
Most stock rims are 7" or 8" you can run 31/10:00/15 or 265/75/15 easy and were stock issue on some . May rub on arms no biggie.
32" tires will fit on stock suspension but if you flex truck wrong (pull into parking lot that is higher than road) you may have some rube issues.
No one mentioned it yet, even though there are many 5 by 5.5" wheels, they may not have the same BS. (BackSpace) or offset. You need to have around 3.75" BS; the proper BS is more important with wider tires.
My '96 EB Bronco has the stock aluminum wheels, and I have 31x11.50x15's on them that fit with no problem. I can't recall a time they ever rubbed, although most of the driving I do with it is on hard surfaced roads.
Any thing 15" Ford 5 on 5.5". '73 year may be dicey. You need to make sure it came off a 4WD rig. (Spindles were way smaller on the cars). Stock rims were 7 to 7.5" wide, 3.5" back spacing. As far as what max tire size, it's a crap shoot. Worn shocks and springs will shrink the max size a bit. Find a bud running something you like. Ask him to swap 'em to your rig and see how they do.