I still have the original AFB too. Finding one that doesn't have worn throttle shafts is near impossible. It will never idle correctly with worn parts that aren't available to buy any more. Along with the shafts and bores that wear, the butterflies and their bores wear too. Re-bushing is not always the answer. Nothing wrong with a new carb. tmm
the Eldle 1406s are probably the cheapest and closest to stock way to go - didn't they buy out Carter? My Carter and 1406 almost look identical. BTW - hope you already have the manifold - 65 273's are different than 67s up.