LS Alm. Block - 9.240/ 4.125 w/Steel Main Caps

The LS Alm. Block – 9.240" / 4.125" w/Steel Main Caps by DART represents the gold standard for LS engine builders seeking a bulletproof foundation for high-performance builds. This aluminum block is engineered for enthusiasts and professional shops tackling everything from street applications to competition-level power plants. The 9.240-inch deck height and 4.125-inch bore diameter make this block a versatile platform compatible with a wide range of LS variants, giving you the flexibility to dial in your exact displacement and compression ratio requirements.

What sets this block apart is the inclusion of steel main caps—a critical upgrade that dramatically improves block rigidity and crankshaft support under extreme loads. Unlike standard aluminum main caps, steel units resist deflection and flex, maintaining precise main bearing clearances even when boost pressure climbs or nitrous systems come into play. The aluminum construction keeps overall engine weight minimal, a decisive advantage for street cars, race platforms, and forced-induction applications where every pound impacts acceleration and handling. The 9.240-inch deck provides ample headroom for modern piston-and-rod combinations, allowing you to optimize compression height and combustion chamber design without sacrificing reliability or durability.

This block suits LS engine builders ranging from weekend warriors building their first stroker to seasoned fabricators constructing twin-turbo or supercharged monsters. Whether you're upgrading a C5 or C6 Corvette, truck platform, or transplanting into a classic chassis, the DART LS aluminum block with steel main caps delivers the strength-to-weight ratio and dimensional accuracy serious builds demand. Installation requires proper machine work and alignment honing to ensure bearing boss concentricity; partnering with an experienced machine shop maximizes longevity and performance headroom. At 132 lbs, this block is significantly lighter than factory iron alternatives, making it the smart choice for builders prioritizing both power and efficiency.