GM late-model performance enthusiastsare currently living through a new golden age of performance. Like what the original Chevy small-block engine did for engine builders duringthe previous 50 years, so now the"LS" series is doing by providing a wealth of performance potential.
At the forefront of development is suburban Detroit's Katech Engines.In fact, Katech was tinkering with LS engines before others really knew they existed. The company has long been a racing engine builder and worked with Chevrolet on the wildly successful Corvette C5-R racing program-a relationship that continuesto this day with the C6.R program.
It was only recently that Katech decided to open its doors to streetoriented enthusiasts, but it has quickly filled the pipeline with a plethora of parts, engines, and obscenely fast street cars. We've recently sampled Katech's 10-second Camaro (seen elsewhere in this issue) and blasted around the 'burbs in a 520-horse, 427-powered TrailBlazer SS.
Neither the company's lightningfast Camaro nor its Texas customer's deceptively quick TrailBlazer would be considered inexpensive projects in most enthusiasts' books, but Katech is reaching out to the performance masses with targeted engine components and short blocks. One of its most interesting offerings is the 7L assembly dubbed the "Value Short-Block."
As its name suggests, the Value Short-Block is a budget-minded 427- inch engine foundation. It includes a balanced and blueprinted aluminum cylinder block, forged crank, rods,and pistons-all preassembled and ready for final assembly with heads,a cam, intake, etc.
Katech lists the Value Short-Block at $6,950, with items such as a camshaft, heads, and a 58X crankshaft trigger available as extra-cost options.The rotating assembly components are first-class items from Cola,Callies, and Mahle.
If nearly seven large seems like a stretch to connote with "budget," consider that a bare C5-R block costs nearly as much without the rotating assembly. An LS7 block costs around $3,000. Throw in the premium rotating parts from theKatech short-block and it's almost like buying the parts and getting the assembly for free.
450-Degree Temperature Differential
Of course, nothing is reallyfree-especially when it comes to building high-performance engines-and Katech squeezes some of the value from its short-block by using a production GM 6L cylinder block and resleeving it in-house with 4.125-inch bore liners.
The sleeves are Katech's design and made of centrifugally cast ductile iron. To install them in the block, liquid nitrogen is used to help create a 450-degree temperature differential between the block and sleeves. This allows the iron sleeves to slide into the aluminum block without the pounding that occurs with a typical press-type fitment.
When the sleeves are seated within the block, the block and sleeves are carefully brought to temperature equilibrium. A special fixture is used to apply torque on the liners toprevent them from lifting duringthe process.
Additional details of the sleevesand resleeving process include:
*The sleeves are machined and inspected, then grouped in sizes within 0.0003 inch.
*Connecting rod clearance is machined into the bottom of the sleeves to ensure adequate clearance for the 4.000-inch stroke.
*4.125-inch bore sleeves for a 427-inch engine have a 0.075-inch wall thickness all around.
*The finished block is double-vacuum impregnated to ensure against leaking.
"With our tight quality control process, we think the resleeved 6L block makes a great product," Katech's Caleb Newman says. "We have seen great success with it in very powerful engines."
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The foundation for Katech's Value Short-Block is a GM 6L production aluminum Cylinder block. Even with Katech's relining of the blocks with new, largerbore sleeves, they still offer a noticeable price advantage over using an LS7 block. | 
Factorystyle main caps, studs, and bolts are used on the bottom, and they'll support close to 600 hp. Extra-strength/ extra-cost options include billet steel main caps that are doweled to the main webs, as well as align-boring and honing. |