According to Chevrolet Parts History GM # 3820875 (1963 models) was replaced in Oct. 1964 with GM # 3844208 (1964-1965 models) which was then replaced in Oct. 1965 with GM # 3841738 (1966-1970 models) which was then replaced in August 1971 with GM # 3993851 (1971-1981 models) which was replaced with GM # 14007355 sometime between Jan. 1982 & Jan. 1985. Currently GM # 14007355 sells for $15.75 at your local GM dealer.
GM # 3993851 first appeared in the 1971 Chevrolet parts catalog (effective Sept. 1970) as indicated with the asterisk (*) following the model year (1971*).
