GM High-Tech Performance Magazine has very detailed coverage of the Katech Performance engine build for the Cadillac CTS-VR. What is a CTS-VR? The VR is the Cadillac CTS-V variant that competes in the SCCA SPEED World Challenge GT Racing Series. Remington Racing runs the previously factory effort with the same factory drivers and cars.
Katech takes a stock, standard LS2 engine as used in the 06-07 CTS-V, and blueprints it for use in the racing car. Blueprinting is the process of checking every tolerance in the engine and selecting values which favor performance. So they basically take the engine apart and assume NOTHING. Everything gets checked, and remanufactured if needed to the optimal values.
The result is an optimal but still technically stock engine. The production CTS-V LS2 is rated at 400hp. The LS2 engine once Katech is done makes over 500hp with a 40% restrictor plate on the intake. Gotta love that. As usual, great article by GM High-Tech Performance Magazine with lots of photos and details so be sure to check it out.
It will be interesting to see if Cadillac is able to race the new supercharged 2009 CTS-V in the series.