Piston ring fits:
1980 - 1988 Merc 115 (6 cyl)
1978 - 1981 Merc 140
1978 Merc 1500XS
1987 - 1989 Merc 35
1984 - 1986 Merc 35 (2 cyl)
1980 - 1983 Merc 40 (2 cyl)
1978 - 1979 Merc 402,40
1986 - 1990 Merc 50 (3 cyl)
1984 - 1990 Merc 60 (3 cyl)
1977 - 1983 Merc 70 (3 cyl)
1984 - 1986 Merc 75 (4 cyl)
1978 - 1983 Merc 800,80 (4 cyl)
1980 - 1986 Merc 90 (6 cyl)
1978 - 1979 Merc 900,90

Timing Belt used on all 3,4, & 6 cylinder Mercury's that have a timing belt.