Loud truck horns is quite a controversial topic product but If you are on the market for some good quality truck horn you should definitely check out the air horns and train horns made by Kleinn. These guys from Tucson, AZ are widely famous for their high quality solutions in this area. Kleinn is a regular attendee of the SEMA Show and a lot of project trucks are equipped with their super horns.
Among dozens of universal applications you will find custom designed kits for Ford F-series that will allow an easy and trouble free installation and usage. These kits are carefully designed to eliminate the necessity to drill holes in your truck.
Check them out on this page: Kleinn | Train & Air Horns at CARiD.com
In this video you can check how is it attached: http://video.carid.com/kleinn/horn/...chevrolet-gm-2500-and-3500-hd-trucks_720p.mp4
Listen how it sounds in this YouTube video:
In the magazines:
Inquire for price quotes, I will be glad to answer all your questions!