The Type 39 was basically identical to the Type 35C except for its engine and was produced in 1925 and 1926. Its engine was modified to be smaller at 1.5 L (1493 cc/91 in³) with a shorter-stroked crankshaft. This brought stroke down from 88 mm to 66 mm, and a mix of regular and ball bearings were used. Ten examples were produced.
An odd 1.1 L (1092 cc/66 in³) version was also created by reducing the bore of the engine to 51.3 mm.
The Type 39A was built specifically for Grand Prix racing, it featured a 1.5 L supercharged version of the straight eight engine. It was only used by the works team and produced a top speed of 185 km/h (115 mph).
Its major Grand Prix wins were in 1926, at the French G.P, San Sebastian G.P and the Italian G.P.