6.4 Hemi

• The contemporary 6.4-liter Hemi powers the 2011 Dodge Challenger SRT8 and Dodge trucks. While the Hemi in 2005 generated as much as 500 hp, the 2010 versions developed 475 hp and 460 foot-pounds of torque. Torque is the twisting forced generated in the Hemi engine. It's often more important than raw horsepower since it gives high-performance cars exceptional off-the-line acceleration, and trucks massive pulling power.
  
  

426 Hemi

• The 6.4-liter Hemi is an offspring of the 1964 to 1972 426-cubic-inch Hemi found in Dodge Chargers and Challengers, and the Plymouth Barracuda, among other Chrysler products. During its eight-year production run, Chrysler never changed the first horsepower and torque ratings of 425 hp and 490 foot-pounds of torque.
  
  

Early Hemis

• The earliest versions of the Hemi appeared in 1951 as the 331-cubic-inch Fire Power V-8s. Smaller versions included 270- and 291-cubic-inch models that developed 245 foot-pounds of torque.