The "teapot" 4200 Holley was used as the primay 4 barrel on FOMOCO products from 54 to 56 and on the 2-4 barrel T-Birds of 57. They were all made to work with the "Loadmatic" all-vacuum distributors. Since I'm putting in a 57-62 centrifigal/vacuum distributor I'm changing the carb to work with it. Late in the 56 year Mercury went to the WCFB.
All the fuel circuits on the 4200 Holley were above the main body of the carb. Rebiult and restored ones go for $400 if you really want one..........JD