The Stovebolt Site Forums The Parking Lot Big Bolts 2 speed rear diaphragm

The GMC p/n is 2211884. They have not been available for many years. I saw a NOS one on eBay a while back that went for $125. I had no interest because the Diaphragm could have been rotten. I have one of these 2 speeds and I intend to modify a 20/20 air chamber to make it work.