[bigblockv6]

You have a 305A with the 1bbl Holley it's not a one year only availability, tis engine was offered in 1960 through 1961 and midyear the 305D 2bbl version was introduced, the 1bbl version was just not adequate for these engines and it's been said many were converted to a 2bbl. my suggestion is get a 2bbl manifold and retrofit it with the Holley 500cfm 2bbl carb and Mr. Gasket #1937 adapter. As far as the Carter fuel pump, most likely the original pump was an AC fuel pump and replaced with the Carter during the rebuild.