I need to replace my very old 14" BF Goodrich tires before something bad happens going down the road...
I know nothing about sizing wheels/tires. But I want to go with 17" Cragar SS wheels. Width would be roughly equivalent of old school "60's" on all four corners.
So I need to know what size tire that translates to with modern tires, and what width wheel I would need. As well as back spacing and offset.

 

I think your car came with F78-14, which are 26.5 in diameter. Looks like 245-50-17 are about 26.6 diameter. I think that's about as close as you'll get. It will look very different with lots of wheel and little tire height. You can look up tire specs (at Tirerack.com) for that size to see what the wheel width would need to be.

 

I just went through this same dilemma when considering wheels/tires for my '71. Decided to keep my '14 inch SS IIs

and went with the ol' school Rad T/As in 225/70. Happy I did. New Cragar wheels are made in China. No thanks. '17s give you that skinny sidewall look that I personally don't care for on the classic GM A-bodies. Just my opinion.

 

Beautiful Cutlass!!

 

I have a set of Torq Thrust 17x8 with 4.5" backspace / 0 offset wheels on order for my '72 Cutlass- with a 245-50-R17 tire, my new combo will be virtually identical in overall specs to my current 15x8 / 245-60-R15 combo. Internet has many tire calculators available to run your numbers so matching up a new combo is simple. I'm also running an essentially stock suspension set up and have no wheel clearance issues.

 

https://www.discounttire.com/learn/tire-size-calculator