CHEVROLET R07 NASCAR SPRINT CUP SERIES ENGINES

Debuted in 2007, the Chevrolet R07 is the successor to GM's SB2 (Small-Block/2nd Generation) engine that was introduced in NASCAR competition in 1998.

The evolution of the GM small-block V-8 racing engine mirrors the development of the GM small-block V-8 production engine, which is now in its fourth generation.  Until the introduction of the Chevrolet R07, all of GM's small-block racing engines shared key dimensions such as cylinder bore spacing, camshaft location and deck height with the original small-block V-8 introduced in 1955.

"The Chevrolet R07 is GM Racing's first purpose-built NASCAR racing engine," said Pat Suhy, GM Racing Group Manager, Oval Track.  "NASCAR's parameters for the new generation of engines provide a range of choices on key dimensions and design features.  Our job was to make the critical decisions and carefully balance the tradeoffs that would enable the Chevrolet R07 to continue Chevy's success in NASCAR.  In the long run, the results will show whether we made the right choices."

Per NASCAR regulations, the R07 displaces a maximum of 358 cubic inches and retains the classic two-valve pushrod design that has been the mainstay of American motorsports for more than 50 years.  The R07's key technical advances over the SB2 include 4.500-inch cylinder bore centers (vs. 4.400 inches in SB2) that enhance coolant flow, a raised camshaft that improves valvetrain dynamics, a new six-bolt head bolt pattern that reduces cylinder bore distortion, and a targeted cooling system that minimizes temperatures at critical locations.

Although the R07 is a purpose-built racing engine, it has strong ties to production powerplants.  "The concepts and processes that are used to improve the performance of our racing engines is shared with the production engine designers to improve the efficiency of our production engines," said Tom Stephens, group vice president of GM Powertrain.

SPECIFICATIONS
Displacement: 358 cubic inches (maximum)
Fuel induction: Four-barrel, 830 Holley carburetor
Horsepower: 890@ 8,500 RPM
Compression: 12:1
Torque: 565 ft/lb @ 6,500 RPM torque
Top speed: 200 mph
Oil: Shell Platinum Plus