How can I outfit a car with a slide whistle?

Question

I was once at a self-cut Christmas tree farm where they had old jeeps that would go out and pick up your tree, all outfitted with slide whistles instead of horns. The slide whistle was mounted on the hood, and seemed to go off when the driver pressed the horn. I've seen lots of slide whistles out there, but none that are designed to be played electrically or mechanically.

Answer 1

Tried J.C. Whitney, Co?  www.jcwhitney.com

Purveyors of car parts and novelties for

cars, trucks, jeeps, and custom since God knows when.

I used to get Moon Hub caps, lakes pipes, and fender skirts from them in the '50s.