I think the main problem is that the wells were designed to hold those really skinny bias ply tires from the '60s. An optional D70-14 has less than an 8" section width, and the standard tires, a 695-14 only had a 7" section width.
Yep, the spare well size goes back to the early A's. My 64 Valiant came with 6.50 x 13 tires. It's just something you learn to live with. This car has 14" tires now but I use a 185-80 X 13 for a spare and it fits fine.
I've converted to BBP on my 68 Cuda and use a donut spare from a 90's Jeep Cherokee. Fits nicely without that unsightly bulge. Modern radials are so much better than the 60's tires and have not had to use it. I did check to see if it fit the car though. I consider spares for emergency use only so see if you can find a skinnier tire for your spare.
