King Engine Bearings MB5505SI001 SI-Series Main Bearing Set Ford V8 351ci 5.8L 400ci 6.6L

The King Engine Bearings MB5505SI 001 is a bi-metal silicon aluminum main bearing set engineered for Ford V8 engines. Part of King's SI-Series lineup, these bearings are built with a K-788 aluminum-silicon alloy construction, delivering reliable performance for OE-replacement and engine rebuild applications involving nodular cast iron crankshafts.

The SI-Series formula uses an aluminum base material strengthened by 2.5–3% silicon content, making it well-suited for medium load engines. The silicon additive improves the crankshaft surface interface, reducing microscopic ferrite peaks on improperly ground or polished nodular cast iron journals.

Key Features:

• Material: Bi-metal silicon aluminum (K-788 SI-Series alloy) — 100% lead-free
• Improved oil clearance to reduce wear and extend engine life
• Reduced operating noise and vibration compared to standard bearings
• Designed for aftermarket gasoline engine rebuilding and performance engines with factory crankshafts
• Improved crankshaft finish compatibility for nodular cast iron crankshafts
• 0.001" undersize — engineered for tighter tolerance fits during engine rebuilding
• Tight dimensional tolerance control for precise fitment and consistent oil film
• Manufactured to King's rigorous multi-stage quality control standards

King Engine Bearings has specialized exclusively in engine bearings since 1960, applying lessons from aviation and motorsport to every bearing in their catalog. The MB5505SI 001 is an ideal choice for rebuilders seeking a dependable, OE-quality replacement main bearing set for Ford's 351ci (5.8L) and 400ci (6.6L) V8 engines.