What wheels did '71 Demons come with?

[Swinger 340]

What size Brakes 9's or 10's small brakes usually always had the smaller wheels. But I have had 10 " brakes with the small wheels also on 318 cars. You could order what you want. But all disc brake cars (no matter the engine) and 340 cars (drum or disc) had 5 1/2 .

You are correct. My 69' 340 Dart had 10" power drum brakes and I converted to stock K/H disc brakes with no problem, being the wheels with already 5.5. AS for the OP question, the wheel stamp is on the inside of the rim, next to the valve stem. Depends on what you are looking for, Ford has a similar stamp, that will also work for you.