"What Is a Hellephant and Why Are They So Rare?", Motor Trend, Feb 11, 2021|"That's the nickname given to the second-generation Hemi that came out in race-only form in 1964, then in street form in 1966 as the "Street Hemi". It got the name "elephant engine" due to its large size, heavy weight, and prodigious, ground-pounding power."