1970-1974 Transmission Controlled Spark Switch 06489785
The Transmission Controlled Spark (TCS) Switch is part of your 1970-1974 Corvette's emission system. Located on the cylinder head, it's job is to override the spark until the engine reaches a set temperature. This allows for vaccuum advance in all gears and prevents stalling after starting.
(Tech Note: Introduced in 1970, the Transmission Controlled Spark (TCS) System controls exhaust emissions by eliminating vacuum advance in the lower forward gears until engine reaches operating temperature.)
Also known under these part numbers: (For reference only)