Porsche's 914/6 variant featured the 2.0 L air-cooled Type 901/3 flat-six engine from the 1967–1969 911T model. This was the least powerful flat-six in Porsche's lineup. This engine had revised pistons that reduced the compression ratio to 8.6:1. The cylinder barrels were entirely made of iron, in contrast to the iron and aluminum "Biral" barrels in the engines in the 911S and 911L. New camshafts had less lift, and relaxed timing characteristics. The venturis in the Weber 40IDT3C carburetors were , smaller than the other 911 engines, and the exhaust pipe diameter was also reduced in size. Power output was . When the 911T got a 2.2 L engine in 1970, the engine in the 914/6 remained at 2.0 L.