Sb 400 Main Caps

The SB 400 Main Caps from MILODON represent a critical component for small block Chevy engine rebuilds and high-performance engine swaps. Designed specifically for 400-journal crankshafts, these main caps provide the structural foundation that secures the crankshaft to the engine block, ensuring proper alignment and load distribution under peak operating pressures. Whether you're restoring a classic muscle car, building a street rod, or assembling a competition engine, quality main caps are non-negotiable for reliability and longevity.

These SB 400 Main Caps feature a four-bolt design with splayed bolt geometry, manufactured from ductile iron for superior strength-to-weight ratio and vibration damping compared to cast iron alternatives. The splayed bolt pattern distributes clamping load more evenly across the cap surface, reducing stress concentration and minimizing the risk of cap walk or crankshaft deflection during high-RPM operation. The rear-position configuration ensures fitment with standard small block Chevy layouts, while the ductile iron construction resists cracking and fatigue even in forced-induction or nitrous-assisted applications.

Engine builders, machine shops, and serious enthusiasts rely on MILODON main caps for both stock restoration and radical performance builds. These caps are essential for any 400-journal small block Chevy crankshaft installation—verify your block's journal diameter and bolt pattern before ordering to ensure proper fit. Proper torque sequence and ARP fasteners are recommended for maximum clamping force and engine stability. For detailed installation guidance, consult your engine build manual or machine shop specifications.