GM started using the letter keys in 1967, and every year after that, the letters changed. They run a 4 year cycle starting in 1967 with the A key being the ignition, and the B key being the trunk. Then in 1968, it was C & D, 1969 it was E & H, 1970 it was J & K. Then the cycle repeated itself.
these years used the same key blanks....
1967 1971 1975 1979 1983 1984 1985 1986 A & B
1968 1972 1976 1980 C & D
1969 1973 1977 1981 E & H
1970 1974 1978 1982 J & K
Not all GM cars used the column ignition lock in 1967, 1968, & 1969, so those cars used the traditional GM Hex and Round head keys. All the rest were the larger rectangular head, and the similar trunk key with the slightly rounded head.
If you have your key numbers, then the best thing is to have the key cut by a locksmith by number. Every time that a key is reproduced, the replacement looses a little of the original detail. Once you get past the 3rd generation of key, it becomes a problem to get the key to work.
The original Hex and round head keys started in 1935, and that series ran till 1966, when the key way was modified to make the "wrong" key not fit into the lock cylinder. This was the beginning of trying to make the cars harder to steal.
these years used the same key blanks....
1967 1971 1975 1979 1983 1984 1985 1986 A & B
1968 1972 1976 1980 C & D
1969 1973 1977 1981 E & H
1970 1974 1978 1982 J & K
Not all GM cars used the column ignition lock in 1967, 1968, & 1969, so those cars used the traditional GM Hex and Round head keys. All the rest were the larger rectangular head, and the similar trunk key with the slightly rounded head.
If you have your key numbers, then the best thing is to have the key cut by a locksmith by number. Every time that a key is reproduced, the replacement looses a little of the original detail. Once you get past the 3rd generation of key, it becomes a problem to get the key to work.
The original Hex and round head keys started in 1935, and that series ran till 1966, when the key way was modified to make the "wrong" key not fit into the lock cylinder. This was the beginning of trying to make the cars harder to steal.
