Corvette Tachometer Filters - Rodney Dickman Corvette Tachometer Filters. Replaces GM Part Number 14020025 Fits 1975-1989 Corvette and most 1975-1989 GM vehicles with HEI distributor NEW from Rodney Dickman! New replacement tachometer filters for 1975-1989 Chevrolet Corvettes, and many other 1975-1989 GM vehicles. Replaces GM Part Number 14020025, which is discontinued. Corvette Tachometer Filter Original Look 1975-1989 Tachometer Filter Original Look 1975-1989. Finally, for the first time in years, Tach Filters are back. We now offer a direct replacement for the OE unit that protects your 1975-1982,1984-1989 Corvette's tachometer circuits from damage. Simply disconnect your old Tach Filter and install the new unit. For your convenience, our unit also comes with longer wire leads for easy installation.