Try an ad in the Swap Meet section right here on this site.

Also check NAPA.
There are newer versions still used, or more recently used on trucks. If you aren't going to be original you may find a cheaper and easier to get perhaps even better replacement for the original. I know my local NAPA has a picture book with a number of different newer ones to pick from.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
---All pictures---
"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-