The 15x5.5 shouldn't rub, the RPO 15" wheel option from '42 is also a 5.5" wheel. I've seen wider wheels used with the stock tie rods on those without rubbing, they key is having the proper backspace and offset.
The oem tire has an average diameter of 28.3". A 215/75/15 comes in at 27.7" average, only about 1/2" shorter overall. A 225/75/15, which really would need a 6-7 inch wheel, comes in at 28.3".
