When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Head to a local junkyard and get a set of factory horns from a late 60's to early 70's Cadillac, big Buick or big Oldsmobile. These will be much louder that the current crop of horns.
These are single wire horns and the brackets will bolt up. Make sure you get the pair of horns from the same car. Each horn is a different note.