SBC 4340 Forged Magnum Crank - 3.750 Stroke SAJ21A-MG

If you're building a serious small block Chevy engine, your crankshaft is the foundation of everything. The SBC 4340 Forged Magnum Crank delivers the strength and precision required for high-RPM performance and reliability, whether you're chasing track records or maximizing longevity in a street-strip combo. The 3.750-inch stroke gives you the displacement and torque characteristics you need without sacrificing rev capability.

This crankshaft is forged from 4340 steel—a material engineered to withstand the extreme loads of forced induction, nitrous systems, and aggressive tune-ups. The internal balance design eliminates the guesswork, reducing vibration and stress on supporting components. Built to tight tolerances and ready to bolt in, this is a no-compromise upgrade for engines that demand reliability at the limit.

• 4340 forged steel construction
• 3.750-inch stroke
• Small block Chevy compatible
• Internal balance design
• 2-piece seal compatible
• Precision-machined tolerances
• High-RPM rated
• MPN: SAJ-21A-MG