The problem with the mounting is the horns have a little spiral like a seashell inside, and the mouth points down. Some of the water that gets shoved in when it rains, goes up over the top and is trapped against the metal diaphragm, which then rusts. I mounted mine pointed up, but drilled an 1/8" hole in the plastic body at the lowest spot when mounted to let the water out. It's only been about two years, but it's still working at the moment. I think I bought my horns from NAPA, they look the same and mount the same, but I had to change the lugs for the wiring weren't quite the same. Probably better to get them from Ford unless the price is way different between the two places.