Hastings, 2.745" bore piston ring set. +.010"

Comes with parkerized cast gray iron compression and oil rings. Used with early style 1929-1949 type pistons with the one-piece cast iron oil ring. Std cyl. bore: 2.745" (69.72mm). 1st ring: 2.3mm (3/32). 2nd ring: 2.3mm (3/32''). Oil ring: 3.2mm (1/8"). Note: OEM 1950-1973 pistons are equipped with 1/16" (1.6mm) 1st. & 2nd rings and late style 3/16" (4.75mm) 3-piece flex-vent style oil rings for improved oil control; for these Hastings rings see 1950-1973 Flathead model years. Above mentioned rings will not fit the 1950-1973 new 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.)