Forget the “Elephant” meet the “Mammoth!”
Sonny’s Racing/Bear’s Performance combine to develop 811-inch real Mountain Motor Hemi
hrysler’s legendary Hemi ® engine has been a high performance engine for over 50 years and has powered every type of race car from sports cars to Indy cars to 330-mph Fuel Funny cars. By the way it is the engine that powers the SS/AH Cudas and Darts that have become so popular in recent years.
With the development and use of the 800+ inch motors in IHRA Pro Stock and Pro Mod, it is a logical thing for a devoted racer/manufacturer who likes “real” Hemi’s -- and perhaps not so much the New Age engines with non-hemispherical chambers -- would develop a “mountain motor” hemispherical engine.
This engine is an 811 cubic incher developed jointly by Sonny Leonard and Bear’s Performance of Ontario, Canada. The Bear’s folks have sponsored and raced Mopars in IHRA Pro Stock for years but with the new hemispherical engine using a head with a “squished” combustion chamber. Now with this new head they can have an 800+ inch Hemi and the heads can either have the true hemispherical combustion chamber or can have heads with the “squished” combustion chamber.
Unlike the old “Elephant” blocks, the new “Mammoth” blocks have a 5.000” bore center, 12.000” tall deck height and 811 cubic inches of displacement. This engine is significantly larger (nearly 50 percent) and Sonny Leonard claims it is more powerful than the 426 Hemi, which represented the high water mark of the engine series. The Mammoth makes a reported 1,700 HP on race gas compared to the smaller Elephant’s original 425 HP factory rating.
ADVERTISEMENT
Bear’s Performance provided the raw head casting which was prepped and assembled by Sonny’s Racing Engines & Components, which finished the project by utilizing these heads with their tried and true mountain motor engine combination.
SOURCE BOXBEAR’S PERFORMANCE SONNY’S RACING |
Long-time IHRA Pro Stock racer Larry O’Brien developed this aftermarket hemispherical head to support his own program as no one else in the aftermarket had such a piece.
“We’re just diehard Mopar guys,” O’Brien, who works at Bear’s Performance, said with a laugh. “We realized we probably should have never started this project after we got into it, but we knew that the only thing to do was to finish it.”
The casting is based on a 5.000 bore center all-aluminum aftermarket block, which is significantly larger than the 4.800 bore spacing used on the original hemispherical blocks. Sonny’s Racing Engines, long known in the industry for its mountain motor engines, already had a number of engines on the market with this block. So, an arrangement was made where Sonny’s would take the raw casting, finish the head and then assemble the first engine for an un-named customer who was planning to run it in IHRA Top Sportsman in 2008.
“Word leaked out about this project and we’ve had a phenomenal response already,” said Rod Short, Sales/Marketing Manager for Sonny’s. “Plans are already in the works to offer this engine as a kit and also to sell the heads separately.”
The engine is legal for use in categories such as IHRA Pro Stock, ADRL’s Pro Nitrous class and truck pulling applications. The 811 hemispherical engine pictured here was assembled for a specific Sonny’s Automotive customer who will run it in Top Sportsman throughout the country in 2008.