INDIANAPOLIS — Chevrolet officials unveiled a new Chevy midget racing engine May 7 at Indianapolis Motor Speedway.
The engine was designed specifically for competition in the USAC Mopar Midget Championship and will be campaigned initially by Tony Stewart Racing.
The new Chevy midget racing engine uses the proven pushrod/two-valve layout that has been the hallmark of GM small-block V-8s since 1955.
“The Chevy midget engine is a clean-sheet-of-paper design,” said GM Racing director Mark Kent. “Most of the engines in the USAC midget series are either based on the four-cylinder Chevy II engine that dates back to the 1960s, or they are a conventional V-8 engine cut in half.
“The opportunity to design an all-new Chevy midget racing engine was an invitation for some of our best and brightest engineers to create an engine within the USAC guidelines that would be competitive in both performance and cost with existing engines. There is definitely a ‘wow!’ factor with the new Chevy Midget engine — every component is recognizable, but they’re repackaged and rearranged in a very innovative way.”
In accordance with USAC rules, the Chevy midget engine displaces a maximum of 166 cubic inches and burns methanol fuel. The inline four-cylinder aluminum block has dry iron cylinder liners, and the aluminum cylinder head has two valves per cylinder operated by pushrods and rocker arms. Maximum output is in excess of 350 horsepower.
“Creating an overhead-valve Midget engine by cutting off one cylinder bank of a V-8 engine positions the camshaft on the intake side of the engine,” explained Dennis Weglarz, manager, GM Racing Powertrain. “Our key design decision was to relocate the cam and pushrods to the exhaust side of the cylinder case. This opened up the intake side of the cylinder head and allowed our engineers to optimize airflow without compromising the intake ports to accommodate the pushrods.
“Relocating the camshaft to the exhaust side also opened up new options in positioning the spark plugs and fuel injector nozzles. It also locates the camshaft lower in the chassis and offsets its weight to the left side of the car, which can be advantageous to handling. The exhaust-side camshaft is really the cornerstone of the Chevy midget engine’s design concept.”
The engine has been tested by Tony Stewart Racing, which is in the process of transitioning to the new engine, and will be Chevrolet’s primary team at least at the launch of this program, but the engine will eventually be available to all USAC competitors through independent engine builders.
The prototype Chevy Midget engines were built and tested at GM Powertrain. Kistler Racing Engines of Fremont, Ohio, supplies the Chevy engines that power the TSR entries. The major components that define the Chevrolet engine package — the cylinder block and cylinder head — will be available to all USAC competitors. Independent engine builders can then assemble Chevy Midget engines using internal components from their preferred suppliers.
“Another important consideration for a grassroots racing series is cost,” said Pat Suhy, GM Racing group manager, Oval Track. “Our objective was to produce an engine that delivered great performance for the money. The Chevrolet brand has always stood for value, and the Chevy midget-racing engine will continue this tradition.”
Suhy told this newspaper the Chevy engine packages would be priced “competitively with other contemporary designs, including Toyota and Mopar.”
“We basically repackaged a conventional engine design. The engine looks identical to almost any other midget engine,” explained Suhy, who says the engines will be assembled by engine builders in a manner similar to other engines, with GM selling the blocks and heads and the builder supplying the remainder of the parts based on the customers demand.
“There will be low-priced and high-priced models,” he said. “We will supply the blocks and heads just like we do in NASCAR, and then the remainder of the cost will depend on what boxes are checked when placing an order.”
Suhy stressed the new GM midget engine is “not exclusive” to Tony Stewart Racing and believes that blocks and heads will be available for other customers in eight to 10 weeks.

Chevy Midget Engine Specifications

Type: inline four-cylinder
Displacement: 166 cubic inches (2.7 liters)
Horsepower: 350+
Fuel: methanol
Bore diameter: 4.150 inches
Crankshaft stroke: 3.050 inches
Deck height: 8.54 inches
Cylinder bore spacing: 4.50 inches
Valvetrain: Pushrod OHV
Valves per cylinder: two
Camshaft drive: gear
Cylinder case material: aluminum
Cylinder liners: “dry” iron
Cylinder head material: aluminum
Fuel system: mechanical FI
Ignition system: programmable electronic
Throttle system: individual runner
Lubrication system: dry sump