Racers who run the GM 602 and 604 sealed crate engines have enjoyed success at shorter "handling" style racetracks around the country for quite some time. And the sanctions they race in have enjoyed solid car counts with good competition. But when racers with those engines show up to a bigger faster racetrack, they are at a disadvantage-a big disadvantage to the beefier open motors that make up the majority of oval track racing.
Racers and promoters who embraced the 602 and 604 have been looking for something more and that something more was horsepower that could compete with an open Super Late Model-style car racing at a bigger track.
In response to this demand, GM engineers opened their bag of tricks and decided to take a modern production engine and turn it into a circle track race motor. Their goal was to come up with a reliable, cost-effective motor that would make power in the 500 horse range. Their platform was to come from the highly successful latest generation LS engine family.
After the engineers put their heads together through many closed door meetings they identified the 6.2-liter LS3 V-8 found under the hood of the Chevy Corvette. In stock trim the motor makes around 430 hp and 420 lb-ft of torque using an aluminum block with six-bolt main caps and high-flow LS3 rectangular-port cylinder heads. To get the power up to where promoters and racers wanted it, GM had to do a little bit of work.
"It has a specially designed circle track specific oil pan and a different cam," says GM's Bill Martens. But perhaps the biggest and most obviously difference between this motor and that one in the little red Corvette is the carburetor and intake manifold. "The carb makes it more familiar to a circle track racer," explains Martens.
The net result of those changes was 525 hp with 471 lb-ft of torque when topped with a 750cfm Holley 4150 carb. The simplicity of those changes point to the versatility of GM's LS engine platform. In fact, LS-based engines have been steadily making their way into the oval track realm thanks to crafty, forward thinking, independent engine builders, but that's a subject for another story.
GUTS Slapping a bigger cam and a carb intake on a Vette motor is just half the story of the new CT525. In a major departure from traditional oval track engines including their own 602 and 604 motors, GM engineers left the coil packs on the engine. That's right gang, just like the LS3, the CT525 has individual ignition coils per cylinder and will require an ignition control system and harness to function. While GM recommends its own controller (PN 19171130) for this application, you can bet there will be plenty of aftermarket versions available by the time you read this.
Choosing to bring an electronically controlled engine to the oval track racing market was a bold move but it was also a highly calculated move. "We will only introduce a product to the racing community if there is a performance and/or cost benefit. By using our current production Corvette LS3, we have the benefit of production savings and uninterrupted availability, with the benefit of a powerful foundation generated from new technology," says Martens. He's not kidding when he says powerful foundation either. LS3-based engines have been known to make upwards of 800 hp without breaking a sweat.