Manley 290740X SBC Rotating Assembly Stroke Bore X-Series Bearings - 355 3.480 4.040

The Manley 290740X is a complete Small Block Chevy rotating assembly engineered for 355 cubic inch builds featuring a 3.480-inch stroke and a 4.040-inch bore. Designed to handle the rigorous demands of both high-performance street and competition racing applications, this kit delivers everything needed for a reliable, power-dense bottom end in a single package.

Kit Includes:

• Lightweight 4340 forged steel crankshaft — heat treated, stress relieved, shot peened, nitrided, and 100% magnafluxed with micro-polished large-radius journals
• 4340 forged steel H-Beam connecting rods with 7/16" ARP 8740 cap screws (ARP 2000 cap screws optional for higher horsepower builds)
• 2618 forged aluminum Platinum Series pistons with premium chrome moly wrist pins
• High-performance piston rings
• Clevite® “H” Series rod bearings (narrowed) and “P” or “H” Series main engine bearings

Key Specifications:

• Engine Family: Small Block Chevy (SBC)
• Displacement: 355 CID
• Stroke: 3.480 in.
• Bore: 4.040 in.
• Bearing Option: “X” Series rod bearings with .001" extra clearance
• Horsepower Range: Up to 900 HP with ARP 8740 cap screws; up to 1,500 HP with optional ARP 2000 cap screws

Note: The 350 and 400 Small Block rotating assemblies are shipped unbalanced. For a precision-balanced assembly, order Manley part number 04000-1 separately. This crankshaft is not intended for use with highly boosted roots-style cog belt superchargers.

Manley Performance rotating assemblies are built to exacting tolerances, making this kit an ideal foundation for any serious Small Block Chevy build requiring maximum durability and proven high-RPM reliability.