Starting with the 1968 172I, Cessna replaced the Continental O-300 6-cylinder engine with the Lycoming O-320 4-cylinder engine. The 172I in particular used the O-320-E2D rated at 150hp. To support this engine, the cowling was redesigned to incorporate a single exhaust pipe extending out from the RH side. The oval-shaped oil cooling inlet located below the spinner was closed off, but its debossed footprint would remain until 1971. The vertical stabilizer end cap was also redesigned to feature a diamond-shaped cross section. (S/N 17256513 ~ 17257161)
Own work
Er-Jin Jang