Originally Posted by Y-Blockhead
Jeff, yes it's the 500cfm, #1403 with electric choke. Be aware that the bores in the secondaries are slightly larger than the "B" manifold and you will need to use a spacer to keep the butterflies from hanging up. I use a phenolic spacer to isolate the carb from heat (you don't need one as thick as mine).
Dennis, I took a look at carb spacers, and man there are more choices than carburetors! With the 1403 and the B manifold, do I want the "4 hole" style or one of the other more open designs?