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Mopar Hemi Engines

In 1963, Chrysler’s executives approved a program to build a car that could win the 1964 Daytona race. According to Tom Hoover, he and Don Moore chose to use Chrysler’s existing expertise in Hemi designs rather than working further with the Wedge, because the Hemi was the cheapest and surest way to be sure of winning.

street Hemi

You Chrysler guys may remember the Race Group's flat-crank Hemis in Room 13. If your feet hurt, 5 minutes in the hall outside would do wonders! — Pete Hagenbuch

According to a 1994 Mopar Muscle interview, Hoover said it was cost effective despite the added expense of the engine because “We knew with the power level we could expect, we could provide performance and win races for minimum expenditure. You could continue to hone and evolve the Wedge forward, but the results would be limited. The cost effective way to make a real impression at Daytona was to take advantage of the A311 Indy program background, and adapt it to the race ‘B’ engine.”

Hemi engine layout

426 HemiTom Hoover said the Street Hemi was not in the plans at the beginning, but that it proved to be easier to produce than the Cross-Ram Wedges, because it could come down the line complete with exhaust manifolds (while the Cross-Ram engines had to have their manifolds fitted later). He and Frank Bilk had tilted the combustion chamber to prevent the exhaust rocker from being too long; this resulted in a narrower engine, so they could do a standard body drop in the Dodge Main factory.

hemi heads

The Hemi Central section was provided by Steve Boelhouwer but we also have these pages:

426 Hemi

Tim Romig wrote: I am the current owner of the Al Corda Hemi Challenger (pictured above). This car was built to promote Hemi crate engines for Mopar Performance and won the 1997 NHRA Championship in the Stock Eliminator class. I purchased the car in 2003 from pro wrestler Bill Goldberg through CIA Cars owner Bob Johnson. I also own a 1972 Plymouth Road Runner that was also sponsored by Mopar Performance in the Stock Eliminator class. It was driven and owned by Dave Hakim, who still works for Mopar Performance.

426 Hemi cross section

Bill Thomas noted: “There were Hemis in boats as well. Chrysler Marine in Marysville, MI made a lot of them years ago and some are still around. Mayea Boat Works of Fairhaven, MI builds some of the finest boats in the world - all custom, all wood, and one at a time. These boats range from maybe 24 to 44 feet long and generally take a year or two to build. The boats are very modern, and very high performance. Years ago Mayea had Keith Black (of Chrysler hemi race engine fame) design manifolds and other parts for Mayea's marine engines. Today, they still build a few Hemis with the same components.

426 Hemi engine dyno test

“A couple of years ago one of their customers brought his boat back to Mayea to be varnished and repainted. He asked to have the original Mayea Chrysler Hemis replaced with a pair of the new GM 502s. Larry Mayea was surprised, but agreed. When everything was done, the boat was nine miles an hour slower with the 502s.

“These are not dragboat engines - these Hemis were made as dependable pleasureboat engines.”

1964 NASCAR race

Modern Hemis 5.7 Hemi • SRT 6.1 and 6.46.4 Truck Hemi • Supercharged “Hellcat”
Classic Hemis 426 HemiOld Hemi History • 392 Crate HemiDevelopmentPlane Hemi

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