stock 67 barracuda rim size?

hey guys so I ran into a predicament, the previous owner of my barracuda did a disc brake conversion on the front, the car came with 6 rims, the two that were already on the front, they already had tires on it, two on the back with shredded tires, and two other rims. so I didn't know that the bolt pattern would change if you do a disc brake conversion? needless to say I put two tires on the two rims that were just hanging out and tried to put them on. it didn't work, the rims didn't line up to the back wheels. so just to make sure I don't buy the wrong size tires, what is the stock barracuda rim size? (I couldn't see them on the rims and the tires are just shredded but the tires on the rim are trailer tires anyway). how can I found out the bolt pattern for the front so I can do the same size disc conversion on the back? also is there any consequences that might happen if I just leave it the way it is for a while? sorry if I did not explain thing clearly or right, I'm still new at cars this old. thanks for the help!