They turn up on ebay now and again.
Before buying one, contact Jon Hardgrove at The Carburetor Shop (573-392-7378) or send him a PM on this forum (goes by the handle carbking).
He'll tell you the exact Carter Carb to look for. There are dozens of different ones that are all similar but with different specifications for different makes and models.
I had a FrankenCarter on my truck. It was cobbled together from a couple different Willys carburetors. Jon helped me with obtaining a correct carb for my engine and a rebuild kit to go with it.
Truck runs and drives with no carburetor problems 4 years later.