<begin Aussie voice> That's not a horn. *This* is a horn: http://www.autosportcatalog.com/index.cfm?fa=p&pid=4751 <end Aussie voice>
Skip Cannon had a pair of these under the hood of his (highly polished) FM II Sunburst. They actually fit. They also sound like a truck horn, not a steroidal Fiat.