 The most historic - 76 & 276 Series (Amal 'Standard' series) can be spigot or flange fixing with adjustment screws on the left or right hand sides of the carburetter body.The available bore sizes are 15/16", 1" and 1 1/16" diameters.The 276 type carburettor is, in virtually all aspects, identical to the 76 version, except that the main emulsion air is drawn from inside the air intake (air filter) whilst the 76 carburettor uses unfiltered air.