Used with late style 1950-1973 type pistons with 1/16″ gray iron parkerized compression rings and the 3-piece flex-vent style chrome oil rings. Also fits 52-56 K; KH; KHK 55″ (900cc) Flathead models. Std Bore: 2.745″ (69.723mm). 1st ring: 1.6mm. 2nd ring: 1.6mm. oil ring: 4.75mm. Note: OEM 1929-1949 pistons are equipped with 3/32″ (2.3mm) 1st. & 2nd rings and 1/8″ (3.2mm) oil ring; for these Hastings rings see 1950-1973 Flathead model years. These rings will not fit the 1929-1949 early type pistons. Tech tip: Piston grooves vs piston rings. It”s not difficult to determine if a Hastings piston ring set will fit a certain piston. You should measure the height of the piston groove in the piston itself. The 2 top grooves will be for compression rings; the lower groove will be for the oil ring. In most cases Hastings oil rings are of the low tension 3-piece flex vent type. Ring heights are listed for reference. Tech tip: Piston oversizes. For each oversize cylinder diameter will increase with .010″ (0.254mm). The standard bore of the cylinder is listed for reference. (Tech tip information provided by Hastings Manufacturing Company; Inc.)
