My 71 chevelle doesn't have a horn. Does anyone know what all is necassary to install a horn as far as parts go?

Assuming that just the horn is missing. You should still have the horn relay on the left side of the radiator. A wire from that to another horn should do it. Most Any 12 volt horn should work.

Nope, I have nothing. There is no sign of horn assembly anywhere unfortunately.

Kind of strange. Did someone rewire the front of the car? The horn relay is where the harness, alternator, and battery wires all come together. Did someone replace the horn relay with a terminal block of some kind?

Just doing a favor and bumping this up.