This product can fit: 

1973 C10, C20, C30, K10, K20, K30
1973 Suburban
1974 C10, C20, C30, K10, K20, K30
1974 Suburban

1975 C10, C20, C30, K10, K20, K30
1975 Suburban
1976 C10, C20, C30, K10, K20, K30
1976 Suburban
1977 C10, C20, C30, K10, K20, K30
1977 Suburban
1978 C10, C20, C30, K10, K20, K30
1978 Suburban
1979 C10, C20, C30, K10, K20, K30
1979 Suburban

1980 C10, C20, C30, K10, K20, K30
1980 Suburban
1981 C10, C20, C30, K10, K20, K30
1981 Suburban

1982 C10, C20, C30, K10, K20, K30
1982 Suburban
1983 C10, C20, C30, K10, K20, K30
1983 Suburban

1984 C10, C20, C30, K10, K20, K30
1984 Suburban

1985 C10, C20, C30, K10, K20, K30
1985 Suburban

1986 C10, C20, C30, K10, K20, K30
1986 Suburban
1987 C10, C20, C30, K10, K20, K30
1987 Suburban