By the middle of 1913 the company had a double version with four rows of five cylinders, rated at 200 hp called the Anzani 20.

An air-cooled motor, its cylinders were made of cast iron, with integral cooling fins.

[3] As with Anzani's other multi-row engines there was significant overlap between the rows in order to bring the big ends close together along the crankshaft.

[1] There were two crankcase mixing chambers, each fed from its own carburettor and distributed by inlet manifolds on the two outer faces of the engine.

[2] The inlet manifold position resulted in the exhaust valves being close to the engine centre line, exiting via short Y-shaped tubes.