LS Iron Block - 9.240/ 4.125 w/Steel Main Caps

The LS Iron Block - 9.240/4.125 w/Steel Main Caps from DART is the foundation of any serious LS engine build seeking maximum durability and reliability. Whether you're constructing a street engine, a weekend warrior, or a long-term horsepower platform, this cast-iron block delivers the structural integrity that modern LS enthusiasts demand. Designed for builders who understand that a quality block is non-negotiable, this component serves as the backbone for everything from naturally aspirated builds to heavily boosted applications requiring robust core strength.

The 9.240-inch deck height and 4.125-inch bore sizing provide exceptional flexibility for stroker combinations and displacement optimization, allowing you to dial in the exact compression ratio and swept volume your build strategy demands. DART's investment in steel main caps elevates this block above conventional cast alternatives, dramatically increasing crank support and reducing flex under high-rpm or boosted conditions—critical when you're pushing cylinder pressures beyond stock parameters. The iron construction dissipates heat efficiently and provides superior longevity compared to aluminum variants, making this block the preferred choice for engines destined for track duty, towing, or extended high-load operation where thermal cycling and structural fatigue pose real concerns.

This block excels in applications requiring bulletproof reliability and proven real-world performance history. Enthusiasts building vintage hot rods, modern restomod platforms, or dedicated performance vehicles consistently choose DART iron blocks for their engineering credibility and track-tested durability. The steel main caps are particularly valuable if you're planning forced induction, high-rev naturally aspirated engines above 7000 rpm, or extreme horsepower figures where marginal gains in structural rigidity translate to engine longevity. At 238 pounds, plan your engine bay packaging accordingly and ensure your accessory drives and support systems accommodate this foundational component's weight and dimensions for seamless installation.