This BluePrint Engines flywheel is engineered specifically for Big Block Chevy crate engines that require a 42.5 oz external balance. Built for strength, smooth engagement, and proper balance, it delivers dependable power transfer and confident operation when pairing your BBC crate engine with a manual transmission. Precision-machined for correct fitment and long-term durability, this flywheel is an ideal choice for street performance builds, restorations, and high-torque Big Block applications.