Unless you lurk around the local IHOP on certain days of the year, there ain’t nothing in this world for free. That’s particularly true when it comes to building horsepower—and as the world of LS performance continues to reach new heights via more boost than there are bleeped-out swear words on an episode of Street Outlaws, the price for dragstrip domination is often more than the cost of pistons and rods.
It comes from picking up the remnants of those pistons and rods after they’ve blown through the 5.3L boneyard block crammed with 20+ psi of boost or a last, fatal hit of nitrous. There have been a number of aftermarket high-performance cylinder blocks over the years, as well as Chevrolet’s own LSX iron block, but Indianapolis-based Concept Performance’s new LSR cylinder block appears to offer the next step up the ladder in building a strong power-adder foundation.
Reinforced six ways to Sunday with features such as eight-bolt main caps, Concept Performance suggests the USA-built block is capable of supporting more than 1,000 horsepower—and perhaps nearly twice that. Better still, it’s aluminum and weighs only about 113 pounds in the standard-deck version, including the main caps.
If the name Concept Performance doesn’t ring a bell, you’re not alone. The company has been around for nearly 20 years as a behind-the-scenes, private-label manufacturer supporting a number of brands you’ve heard of. This is their first real foray into direct marketing, but it is based on years of casting experience. In that time, they have learned what works and what doesn’t when it comes to building a strong race block. For the basic LS design, the key was eliminating flex, which is why you see reinforcing ribs and triangulated braces throughout the casting.
Like other aftermarket blocks, the LSR is designed to accept Chevrolet’s production-based cylinder heads, as well as the six-bolt LSX heads. It is available in a standard 9.240-inch deck height and a 9.750-inch…