Carter's sales slogan in the 1950's was "The ABC's of fuel systems- - - -Always Buy Carter!" There's a very interesting story about Carter producing direct-replacement carbs for Rochesters, and the CEO of Carter vowing to sell a million of them. It took a few years, but when the one-millionth carb came off the production line, it was gold plated and presented to the CEO of GM. Patching up a Rochester will keep a stovebolter too busy to engage in very many vices in his spare time, though!
If the spacer (actually a heat insulator) is flat, it doesn't need a gasket on the manifold side. Scuff it on a piece of sandpaper supported by a sheet of glass to check for flatness. Be sure the carb to spacer gasket has slots in the proper location to prevent blocking off the vacuum passages.
Jerry
