Tire & wheel sizes for 71 thunderbird

Hi guys, thanks for letting me join this forum. Would like to ask if I want to put 22 inch rims on my car, is that possible? If so how wide can i go without modifying arches, if not how big can i go..cheers
I put 17x8 rims with 275/50-17 tires on the rear of my 79. That was about as wide as would work with no offset. There was plenty of room to go bigger in diameter, but not wider. That figures to a 4.5 inch backspace. I'm guessing your 71 will be similar, but don't know for sure.