Well its a I6 so it is efficent just saying that. Good ballanced engine. They ran log intakes till the late 80's, so they had to be ok some were. Good set of gears and a light foot I could see 23 MPG. Mine runs at 180. Thats a good temp. New cars have to run at 200 to help with all the egr crud. Not the best I6 ever but it aint the worst.
Sorry inline 6 fan.
