The Chrysler Hemis have had a few series....one of first Hemis though was not an automotive engine, it was an experimental inverted V16 built for Republic's P-47 fighter plane (normally powered by a Pratt & Whitney R-2800) to push the piston powered prop engine envelope these never made it into production but were reportedly clocked at 505 mph. These beasts were built at Republic's Farmindale Long Island plant from 1941-1945, we used to live near there and was able to drive through the huge compound before it shut down in 1987. When jets came on the scene, no more need for piston powered fighters but they kept experimenting with Hemi head combustion chambers....
Gen 1 was early 50s, then replaced with the Wedge series (413, later 426, these became the first factory super stock drag cars)....
Gen 2 was 1966-1971 426 cu in (7 liters) Hemi was dropped after 1971, they continued with the wedge series 383 and 440 engines....
Gen 3 started in 2003, 5.7 liters, then up to 6.1, then 6.4
These engines are very common here, used in Dodge Ram pick ups extensively.
I'm a Jeep guy I've driven a number of Jeeps with the very good Pentastar 3.6 liter V6 but the Hemi in a Grand Cherokee is just in a different league.