Fuel Injector, 4.3/5.7 >07 IAF R Fuel Injector used in 4.3L and 5.7L post 2007. Injector contains one red and one blue o-ring. Older models use. If you have an older model see part number 446105. Mercruiser – Fits many MCM 4.3L MPI engines (s/n OM300000-1A063239) and many 5 0L 5 7L & 6 2L MPI.