What does code 421 mean?

Answer 1

421 can be the code for the engine size generally found in muscle cars. 421 cubic inches = 6.9 Liters. It was develloped by Pontiac as a V8 engine. The 421 SD became factory installed in 1962 and in 1963 a street version became available from the factory with a four barrel or tri-power carburation. The Super Dutyversions of this engine were extensively used in NASCAR stock car racing and drag racing competition.