Happy Hemi Day!

That's the unofficial designation for April 26, at least among the "Mopar or no car" crowd.

It's a reference to the numerical version of the date, 4/26, which corresponds with the displacement of the 426 cubic-inch Hemi V8 of 1964-1971 that is affectionately known as "The Elephant."

A drag racing version of the 426 Hemi V8 debuted in 1964

A drag racing version of the 426 Hemi V8 debuted in 1964 (Mopar)

The engine was one of the second generation of Chrysler Corporation V8s to feature a hemispherical combustion chamber and became a legend when it was banned from NASCAR after dominating its debut season.

Richard Petty won his first Daytona 500 in 1964 at the wheel of a Hemi-powered Plymouth Belvedere

Richard Petty won his first Daytona 500 in 1964 at the wheel of a Hemi-powered Plymouth Belvedere (ISC Images & Archives via Getty Images)

Chrysler continued to develop it as a drag racing motor and launched a mass-market street version in 1966.

The 425 hp engine was available in several models, including the 1971 Plymouth Hemi 'Cuda Convertible, of which only 11 were made and just two sold in the U.S. with a 4-speed manual transmission. The only one of them that still exists with its original powertrain was auctioned in 2014 for $3.5 million.

This 1971 Plymouth Hemi 'Cuda Convertible was sold at auction in 2014 for $3.5 million

This 1971 Plymouth Hemi 'Cuda Convertible was sold at auction in 2014 for $3.5 million (Mecum Auctions)

The Hemi name was resurrected for a new generation of engines in 2003 and is still in use by Dodge and the Mopar parts division today.

In 2019, the automaker celebrated Hemi Day with the launch of a modern 1,000 hp supercharged 426 V8 called "The Hellephant" that's available for custom car builds for $29,995.

CLICK HERE TO GET THE FOX NEWS APP

The SpeedKore Hellraiser is a custom 1970 Dodge Charger powered by a Hellephant crate engine.

The SpeedKore Hellraiser is a custom 1970 Dodge Charger powered by a Hellephant crate engine. (SpeedKore)

Comic superstar Kevin Hart recently picked up a 1970 Dodge Charger powered by one that's been nicknamed Hellraiser.