The installation of this oldtimer part was necessary, if a six-cylinder in-line engine had to be combined with a twin register carburettor. A look at the flange to the carburettor tells us more than a look at the carburettor itself. The three left inlet manifolds are supplied from the lower part, the three on the right, from the upper part of the twin register carburettor. Because of the common control of the throttle valves and the choke flaps, the first stage must always be arranged on the left and the second stage on the right. Typical for each part is - mostly, but not always - the smaller first stage and the larger second stage. On the flange to the cylinder head one can envisage the order of the 2 valves each per cylinder: A-E-E-A-A-E-E-A-A-E-E-A (from left to right).