This listing is for a brand new set of moly piston rings from Hastings Manufacturing that are made in the USA. Set includes the rings for 8 pistons. Part Number: 2M683 Bore Size: 4.250" Top Ring Width: 5/64" 2nd Ring Width: 5/64" Oil Ring Width: 3/16" This set of rings are compatible replacements for the following engines that have 4.250" bore size and ring groove widths of 5/64" x 5/64" x 3/16". 427 CID (7.0L) 1966-1969 454 CID (7.4L) 1970-1990.