Well that's what I had, I've had this car badge with an engine capacity on it for must be over 15 years. I bought it in a junk shop for $5. And here it is:
For over 15 years I knew it was off an American car but had no idea what car or even make it was off.
I assumed it was a "BOP" product as it wasn't any common size big block I'd heard of, you know 440, 427, 454 etc.
So during lunch time at work I looked it up and found it was a designation for a fairly rare engine.
"In 1961 Pontiac continued to push the horsepower upwards with the release of the 421 engine. As with all other Pontiac V8 motors that evolved from the 316 V8, the 421 was simply a bored out and stroked version of the popular Pontiac 389 V8. What was most interesting about the 421 engine in the beginning was that it was a dealer installed option only known as the SD (Super Duty) 421. These motors were built mainly for NASCAR or other racing purposes and were equipped with all the extra racing goodies that people were looking for. A Pontiac SD 421 came with forged steel rods and crankshafts for extra durability. In 1961 and 1962 they were available with either one 4 barrel carburetor or a dual 4 barrel carburetor setup depending on whether the buyer wanted to head to the racetrack or drag strip.
By 1963 Pontiac decided it was time to release the 421 V8 officially to the general public and the motor would continue to be available until the end of the 1966 model year. The 421 SD Tri-Power engine offered during these years produced the highest horsepower of any motor in the Pontiac V8 lineup at 376 bhp. There were a few 1962 Grand Prix models that came with a 421 SD from the factory so if someone is lucky enough to have one today then they have a car that is probably worth some decent money simply because of the rarity of these models."
“Introduced in 1961 as a dealer-installed Super Duty option that had dual four-barrels, the 389 was bored to 4 3⁄32 inches (103.98 mm) and stroked to 4 in (101.6 mm) for a displacement of 421.19 cuin, and also featured larger 3.25 in (82.55 mm) main journals. Unlike previous enlargements of this engine, it did not replace the 389. 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 carburetion. The Super Duty versions of this engine were extensively used in NASCAR stock car racing and drag racing competition. The 421 also marked the end of the option for a forged-steel crankshaft. The Armasteel cast crankshaft was the standard crankshaft of the entire Pontiac V-8 line until 1967. While "Armasteel" was no more than a fancy name for a hardened cast-iron unit, it did refer to the "locking ball" as opposed to the "flaking" type cast-iron found in other engines. In 1967, Pontiac out of concerns the public misunderstood the engineering terms, went to a Nodular cast-iron name crankshaft, which they used until 1975.”
Judging by the type of badge mine is, I'd say it came off of a 1966 Pontiac Catalina 2+2 given that's where most 421s ended up, at least from what I've read and from pictures. The Grand Prix didn't seem to have the same badges or at least not in the same place and the back of the badge has the part number 9784727-RH on it which marks it as a 66 Catalina part RH fender :)
Anyone know anyone that needs one? I'd like to see it back on a car, but I only have the Right hand one.