40-3020903 Head gasket, Hercules model G3400 engines. Superseded numbers were 40-3020902 and 287218 750-11280 Part number for the military

Part number for the military gasket is 186-6112 and the NSN part number is 5330-01-362-6111

50520 OEM oil pressure sensor

these engine were commenly used in the Read ScreenAll screeners

ID 3 5/16"

These are factory manuals not cheap copies

40-3020903 Head gasket, Hercules model G3400 engines. Superseded numbers were 40-3020902 and 287218 750-11280 Part number for the military40 3020903 Head gasket used on the 3400 series 6 cylinder Hercules engines, both Diesel and Gas types. Old part number will be listed as 40 3020902 and 287218. There maybe some variation in appearance depending on OEM manufacturer. This will be item number 16 in the Hercules drawing NSN 5330 01 389 0704, NSN 5330 00 133 0811