421 - 3.875" Stroke

Manley  “Pro Series” 4340 alloy steel crankshafts are available with many value packed and high-performance enhancing features for a wide range of domestic engine applications.

Features

• Lightweight Design, 4340 Non-Twist Forging: Our crankshafts feature a lightweight 4340 non-twist forging, ensuring durability and performance.
• Enhanced Strength: A multi-step heat treatment process and nitriding enhance the crankshafts’ strength and longevity.
• Micro-Polished Journals: Large radius journals are micro-polished to reduce friction and enhance performance.
• Rigorous Quality Assurance: Each crankshaft undergoes stress relief, shot peening, and 100% magnafluxing to meet our stringent quality standards.

Crank Polishing Upgrade

Extends bearing life, reduces oil temp, frees up a slight amount of average horsepower. This is a very low cost upgrade, and in the world of mass production, most cranks do not come with a true polished finish. This is why most machine shops have a machine to do this. The difference is dramatic between a crank right out of the box and one that we have polished. Bearing companies claim that cranks that have better finishes on the journals will survive the break-in better, and have much longer bearing life. We do a two-step process and bring the RA numbers down in the single digit range. We have the most advanced crank polishing machine on the market.

Cost for the crank polishing upgrade is $39.50. Before you finalize your purchase of this crankshaft you may add this upgrade to your shopping cart.

Product Information