I had one on old black truck & it worked well after a simple soak & kit-truck got 16mpg & purred like a kitten, although it was obvious it had never been rebuilt before. I had another B on a 66 GMC that simply dumped fuel down the intake, the top was warped so bad fuel could be seen dripping off the venturi, & the idle mixutre screw was simply for looks. I guess time & many ham-handed rebuilds kills many B's. Have you tried eBay, sometimes NOS B carbs pop up? Yes, they would likely need a new pump but it would be new & possibly not warped.
