This product has been discontinued by the manufacturer and has been superseded by Sierra 18-8804-1CDI 631-0008 Mercruiser Spark Plug Wires - 8 QTY This is a set of CDI 631-0008 Mercruiser Spark Plug Wires for 8Cyl Thunderbolt. Fits: Mercruiser; 1983-1984 198, 5.0L GM; 1985-1995 200, 5.0L GM; 1985-1986 228; 1981-1995 230, 5.0L/LX MIE; 1987-1995 260, 350MAG 5.7L SKI/Alpha/Bravo; 1982-1994 260, 350MAG; 1985-1989 300, 20EFI; 1981-1992 330, 340, 7.4L MCM & MIE; 1991-1996 350 MAG SKI GM; 1985-1987 370 TRS; 1986-1997 454MAGALPHA; 1990-1993 502MAG; 1991-1995 525 SC; 1990-1996 8.2L GM MPI MIE; Replaces: 18-8804-1; 84-816608A61; 847701K4; 84-847701Q4; 9-28002; 631-0008;