Manley Chevrolet LT1 Directed Injected 4340 Forged 4.00in Stroke Pro Series Crankshaft

Starting with a 4340 non-twist forging, this Manley Pro Series crankshaft is built for serious performance in Chevrolet LT1 engines. The 4.00-inch stroke is a key dimension that influences displacement and power potential, and this forging process ensures it’s built to last under demanding conditions. It’s designed to handle the stresses of high-performance builds, offering a solid foundation for your engine project.

Manley has incorporated several features to enhance both durability and performance. The crankshaft is gun drilled at the mains and the rod journals are lightened, contributing to a lower overall weight which helps the engine rev more freely. The counterweights are carefully profiled for precise balance, crucial for smooth operation and longevity at higher RPMs. To further boost its resilience, the crankshaft undergoes a multi-step heat treatment and nitriding process, significantly increasing its strength and resistance to wear. The large radius journals are then micro-polished to minimize friction, allowing for better oil flow and improved overall efficiency.

Every crankshaft is put through rigorous quality assurance steps, including stress relief, shot peening for fatigue resistance, and 100% magnafluxing to detect any potential flaws. This attention to detail ensures that each unit meets Manley's high standards before it leaves the factory. If you're rebuilding your LT1 top end and need a crankshaft that can handle significant power, this Pro Series unit is a well-built option.