The Stovebolt Site Forums The Shop Area General Truck Talk Does anyone know what these brackets are?

Excellent, Brad

So, 1953, the standard "seashell" horn mounts on the intake manifold.
And, the accessory "seashell" horn mounts on the firewall.

Now, I hope I will remember to go to my garage tomorrow, to see/show that there were "seashell" horns that had mounting posts on them, that are in different locations compared to 1953/1954/1955st truck horns.