Hello all Any expert in these carburetors that can decipher the letters identifying vacuum ports ?. What are M, A, L, N, J, H as cast on the carburetor body intended for ? Vacuum schematics are vehicle oriented and often do not tell the port 'letters' From the point of view of the carburetor, is there a chart telling the use or function of such ports ? -Not the vacuum/hose diagram- Also, is the 2GE model meaning 'E'lectric choke ? This is about a Rochester 17058448 to be used on a 305 engine with no emissions equipment and want to know the bare basics on where to hook booster vacuum, distributor (ported or not), and what ports to leave unused, capped.