This piston for 1098cc engines was designed with 4 rings. The top three compression rings are .0625" thick and the bottom oil ring is .1575" thick. Pin height in this piston design is 2.2855", this results in a compression of 8.5:1 in most standard applications that include the '62-'67 A40, MKII 1100, the '747-'81 Allegro 1100 and the '75-'80 Mini Clubman and Clubman Estate.