King Engine Bearings MB3331SI0.25 Main Bearing Set for Subaru 1300/1600 +0.25mm Oversize

The King Engine Bearings MB3331SI0.25 is a +0.25mm oversized main bearing set engineered for classic Subaru 1300 and 1600 engines. Built using King's proven SI-Series bi-metal construction, these bearings feature an aluminum-silicon alloy material that delivers reliable performance for medium-load engines and nodular cast iron crankshafts.

Key Features:

• SI-Series Bi-Metal Construction — Aluminum base material strengthened with 2.5–3% silicon for excellent durability in medium-load applications
• +0.25mm Oversize — Designed for use with reground crankshafts machined to a 0.25mm undersize
• Bull's Eye Tolerance™ Technology — Proprietary production process combining precision machining, overplating, and computerized wall thickness monitoring for shell-to-shell consistency
• Aftermarket Engineered — King offers a wider range of undersizes and material options than OEM, making this a superior replacement choice
• Trusted by Aerospace and Racing — King's engineering standards are derived from experience in aviation and motorsports applications

King Engine Bearings has been manufacturing precision engine bearings since 1960, with a singular focus on quality and engineering excellence. The MB3331SI0.25 main bearing set is a reliable solution for engine rebuilders restoring or refreshing early Subaru flat-four engines that require crankshaft grinding and oversize bearings.