| The Chrysler Corporation built three generations | | | | hence the name Hemi, which is short for |
| of Hemi engines. The first generation was known | | | | hemispherical. The combustion chamber allows for |
| as the Firepower engine and was manufactured | | | | angled rather than side by side valve |
| from 1951-1958. The second generation Hemi was | | | | arrangement, which creates more space inside |
| built from 1964-1971, while the third and current | | | | the chamber roof. More space enables the use of |
| generation began in 2003. It should be noted that | | | | bigger valves. It also straightens the airflow |
| Chrysler also designated the four cylinder | | | | passage through the chamber head. In other |
| Mitsubishi 2.6L engine as a Hemi. The first run of | | | | words, the better the airflow, the more power |
| Hemis finished out in 1958 with the 390hp 392-cid. | | | | that can be generated from piston displacement. |
| The company killed the engine because it was | | | | In order to facilitate complete combustion, the |
| heavy and expensive as well as a bit complex to | | | | spark plug is located at or near the center of the |
| manufacture. | | | | chamber. Experts say it is best to used dome |
| In the 1960's The company was bitten again by | | | | topped pistons in order to maximize compression |
| the NASCAR bug and wanted to again dominate | | | | ration. While Chrysler is the only manufacturer to |
| drag racing. Chrysler went to work and came up | | | | use the name Hemi, nearly all engine |
| with another incarnation of the Hemi, this one | | | | manufacturers offer similar design elements. |
| based on 413/426 wedge-head engines. The 426 | | | | The 426 Hemi head has intake and exhaust valve |
| Hemis were installed and debuted in 1964 | | | | stems pointing in different directions. This |
| sweeping the top three spots at the Daytona 500 | | | | configuration mandates a larger cylinder head as |
| in February of that year. The stock car racing | | | | well as a complex rocker arm geometry in both |
| Hemis had a single four barrel on top of a dual | | | | the cam in block and the overhead cam engines. |
| plane high rise intake manifold used with a four | | | | Hemi combustion chambers lack the so called |
| speed manual gearbox. The drag racing version | | | | quench area found in wedge combustion |
| featured ram tuned aluminum induction systems | | | | chambers. What this means is that the hemi |
| with dual quads. These early models also made | | | | engine is more sensitive to gasoline fuel octane, |
| use of the torqueflite automatic or four speed | | | | meaning the higher the octane the better the |
| push button transmissions. | | | | engine runs. |
| The 1964 426 Hemi is bowl shaped in appearance, | | | | |