[1][2] There is no carburetted version of the engine, which would have been designated O-390 and therefore the base model is the IO-390.

It features a tuned induction system, roller tappets and Slick Start ignition.

It has a factory recommended TBO of 2000 hours and requires a dynafocal engine mount.

[7] In November 2009 Lycoming announced that it had obtained an FAA Supplemental Type Certificate to replace the originally fitted Lycoming O-360 engines in the Mooney M20E, M20F and M20J with a new or remanufactured IO-390-A3A6 engine.

[8] Also on November 12, 2009 Commander Aircraft received an STC for its model 112B using the MTV-12-B/188-59b propeller.