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426 Hemi Engine Specs

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The All New 426 Hemi

The All-New Gen III 426 Hemi

The 426 Hemi was the first version of the hemispherically shaped combustion engines to be marketed by the name Hemi in 1964. This engine was made by Chrysler, and Chrysler had in fact been creating engines with this designed since the early 1950’s.

The 426 Hemi was given the nickname “The Elephant” due to its large size and enormous amount of power.

This engine was made primarily for NASCAR racing purposes originally, but was later available in street cars as well. The customer cars that this engine was available in were primarily Dodge and Plymouth cars.

For Dodge, this engine was available in the Coronet, Charger, Dart, Super Bee, and Challenger.

From Plymouth, this engine was installed in the Satellite, GTX, Barracuda, Road Runner, and Superbird. The 426 Hemi was also available in the Monteverdi Hai 450 as well.

In the early 1960’s, Chrysler decided that they wanted an engine that would dominate the NASCAR circuit. Beginning in 1964, the engine was used for NASCAR purposes, and this engine dominated from the beginning by taking the top 4 spots in its first Daytona 500.

The primary reason that this engine was ever available in street cars was due to NASCAR mandates that they must produce more of these engines for it to be allowed in NASCAR races. The first street version of the 426 Hemi was sold in 1966 and the engine was ultimately phased out in 1971. It was never truly mass produced due to its high cost and large size.

426 Hemi Performance Specs

The power of this engine made it very popular, especially for performance enthusiasts, and this engine could still be found in drag racing cars to this day.

The 426 Hemi, named for its 426 cubic inch displacement, was introduced with 425 horsepower at 5000 RPM and a peak torque of 490 ft-lbs at 4000 RPM for its street version.

The NASCAR version was much more powerful, as the NASCAR version had a 12.5:1 compression ratio, compared with the 10.25:1 ratio in the street version.

The performance specifications remained the same throughout the production life of the Hemi. This is quite a significant statement as the calculation for horsepower ratings was changed from gross to net during this time, but the 426 Hemi maintained the same power rating.

This would indicate that the original rating of 425 horsepower gross was likely far less than the actual performance capability of this engine, and more likely took this power rating to be common with its cubic inch displacement. This engine had a bore of 4.25 inches along with a stroke of 3.75 inches.

Head and Block Specs

The 426 Hemi used a cast iron block for all of its offerings. The NASCAR version of the 426 Hemi cylinder head was made from Aluminum alloy; however, the street version of this engine used a cast iron head for improved durability.

This engine used a traditional camshaft overhead valve (OHV) design with 2 valves per cylinder. The original engine used solid lifters, but hydraulic lifters were implemented beginning in 1970.

The 426 Hemi was a revolutionary engine that produced lots of power and is still extremely popular to this day. The story of this engine performing at such a high level with its initial introduction shows the superior design of this engine.

Unfortunately this engine was not used frequently enough in normal production to allow for a long production life, as the engine was phased out only 7 years after its inception. The fact that this engine is still used in drag cars consistently is a testament to this engine’s power.