Manley 290730HX SBC Rotating Assembly Stroke Bore HX Bearings - 355 3.480 4.030

The Manley 290730HX is a high-performance rotating assembly engineered for Small Block Chevy (SBC) 355 CID applications. Built around a 3.480" stroke and designed for a 4.030" (+.030") bore, this kit delivers the precision-matched components needed to build a reliable, high-output engine from the bottom up. The "HX" designation indicates this assembly is supplied with Manley's optional HX Series main bearings featuring .001" extra clearance for enhanced oil film and added protection in high-performance builds.

Key Features:

• 4340 Forged Steel Crankshaft – Lightweight forged construction for superior strength-to-weight ratio
• Pro Series Lightweight I-Beam Connecting Rods – Supplied with 7/16" ARP cap screws; rated up to 750 HP with ARP 8740 or up to 1,500 HP with optional ARP 2000 cap screws
• 2618 Forged Aluminum Platinum Series Pistons – Flat top, -4cc dish design; paired with premium chromoly wrist pins
• Total Seal Piston Rings – 1/16", 1/16", 3/16" ring pack included
• HX Series Main Bearings – Clevite "H" Series with .001" extra clearance for optimized oil clearance in performance applications
• Clevite H Series Narrowed Rod Bearings – Matched for use with micro-polished large-radius journals
• 355 CID Displacement – 3.480" stroke / 4.030" bore / 6.000" rod length
• Compression Ratios: Approximately 11.2:1 w/58cc, 10.4:1 w/64cc, or 9.1:1 w/76cc chamber volume

Designed for use with a standard 350 engine block and 350 main journal diameters. Note: The 350 and 400 Small Block rotating assemblies are supplied unbalanced; order part number 04000-1 separately for precision balancing. This assembly is not intended for use with highly boosted roots-style cog belt superchargers.