Plain Steel Wheel Source

I just purchased a 1968 Dart 270, and I am new to the forum.

I tried searching the site for info, but I was unable to find it, so I'm posting this thread. My apologies if I'm asking questions that have been previously answered

My car is equipped with 13" wheels and large wheel covers.

I understand that 14" wheels were available on some 1968 Darts.

My questions:

1. Is my understanding correct?
2. What size 14" plain steel wheel and tire is correct for the 1968 Dart?
3. What size new radial tire is closest to the original 14" tire?
4. Where can I purchase a set of the correct 14" plain steel wheels that will accept the large wheel covers?

Thanks.