One of the tough things I have been searching for is a horn for a 67-68 with airconditioning. Ford had to relocate the LH horn on AC equipped cars to make room for the coolant lines to pass through the core support to the condenser coil. They moved it to the top LH corner of the condenser and it was mounted with the same bolt as the condenser. The unique thing about it is that the horn mount is shaped to fit the condenser rail. Making these guys really hard to find.
I was judging a local show today and there was a 67 fast back that was newly restored that I noticed that he had reversed the hi and low horns. After looking closer I could see that one of them was a AC horn and it was a non AC car. After the show I was talking with him and offered to replace the AC horn with the correct one and a few other small things his car needed. Wow what a great day I got my needle in a haystack and got to help someone else too.