Hemi. Few words in the automotive world are more instantly recognizeable than this legendary term. From its original stock car roots to its eventual domination of the world of drag racing, the 426 Hemi has left an indelible stamp on automotive history.

Chrysler produced their first engines with hemispherically-shaped combustion chambers in the 1951, but these early motors (301, 331, 354, and 392 cu. in.) share nothing in common with the 426 except for spark plug location and basic valve train arrangement. These "old style" hemi's were primarily passenger-car motors, although later versions did power the legendary Chrysler 300 "letter cars" until 1958. Chrysler referred to these engines as the "Red Ram", "Firedome" and "Firepower" motors throughout their production. Horsepower peaked in 1958 with a 2-4bbl version of the 392 rated at 390 hp. Today, these motors are difficult to find, and those which aren't in restored vehicles are most often found in fuel dragsters and funny cars, running on alcohol.

When the 426 Hemi was introduced in 1964, it was strictly a racing engine. On February 23 of that year, four Hemi-powered Mopar's swept the Daytona 500, finishing 1-2-3-4. This single event caught the racing world by surprise and eventually prompted NASCAR to impose stricter production rules on Chrysler. Instead of producing only a few blueprinted Hemi motors each production year, they would instead have to produce several thousand and sell them in "ordinary" production vehicles. Fortunately, Chrysler didn't throw in the towel on the hemi after this (although they did sit out the 1965 season), and the end result was the slightly detuned street hemi which first appeared in 1966 B-body Dodges and Plymouths.

The street version differed from its racing cousin by virtue of a lower compression ratio (10.25:1), milder valve timing, and different intake and exhaust manifolds. For reliability, cast iron heads were used instead of aluminum. Very little changed inside the 426 Hemi throughout its eight-year production life; only differences in camshaft design (more duration was added in 1968, and a hydraulic bumpstick was used beginning in 1970) really separate the model years. Chrysler never changed the engine's advertised horsepower and torque ratings, which stood at 425 hp at 5000rpm and 490 foot-pounds of torque at 4000 rpm.

To list the races which 426 Hemi-powered cars have won would be impossible. Although the motor was basically legislated out of NASCAR in the 1970s, and emissions laws, high production costs, and the insurance industry stopped production of the street version in 1971, the motor still dominates the top drag racing classes more than twenty-five years later. Additionally, aluminum versions of the block power virtually all top fuel dragsters and funny cars, and are often used in drag boats and "monster" trucks. Restored Hemi muscle cars carry astronomical prices.

Although it's been a quarter of a century since the last Hemi-powered car rolled off a Chrysler assembly line, and the chances of finding a Hemi car in a used car lot or junkyard are slim to none, all is not lost for the modern-day Hemi enthusiast. In 1993 Mopar began manufacturing a new Hemi block, and since then almost all of the other Hemi parts have also been re-introduced. Although complete engine assemblies are not available, a competent engine builder can now assemble a complete, brand-new Hemi engine for around $10,000.

[Allpar note: Chrysler has developed a new 5.7 Hemi generating over 340 horsepower]

FOR MORE INFO ON THE HEMI VISIT WWW.HEMI.COM