Enginetech BC299J.030 0.030 Undersize Main Bearing Set for 1977-1981 Buick Oldsmobile Pontiac 4.3L/4.9L - Complete OEM-Spec Main Bearing Set

Enginetech BC299J.030 is a 0.030 undersize main bearing set for 1977-1981 Buick, Oldsmobile, Pontiac 4.3L/4.9L 265-301ci V8 engines.

Important Notes:

• Sized for crankshaft main journals machined .030 inch undersize. Measure journal diameter before installation - installing on the wrong journal size will cause immediate clearance failure.
• Always replace main bearings as a complete set. Never mix new bearings with used bearings - uneven wear and clearance differences will cause premature failure.

Complete main bearing set covering all main journals for the V8 application - one set required per engine.

Fitment:

• 1977-1977 Buick Skylark 4.9L 301ci V8
• 1977-1977 Pontiac Grand Safari 4.9L 301ci V8
• 1977-1977 Pontiac Ventura 4.9L 301ci V8
• 1977-1977 Pontiac Firebird 4.9L 301ci V8
• 1979-1979 Pontiac Firebird 4.9L 301ci V8
• 1977-1977 Pontiac Grand LeMans 4.9L 301ci V8
• 1979-1979 Pontiac Grand LeMans 4.9L 301ci V8
• 1977-1977 Pontiac LeMans 4.9L 301ci V8
• 1979-1979 Pontiac LeMans 4.9L 301ci V8
• 1977-1979 Buick LeSabre 4.9L 301ci V8
• 1977-1979 Pontiac Bonneville 4.9L 301ci V8
• 1977-1979 Pontiac Catalina 4.9L 301ci V8
• 1977-1979 Pontiac Grand Prix 4.9L 301ci V8
• 1978-1979 Pontiac Grand Am 4.9L 301ci V8
• 1978-1980 Pontiac Bonneville 4.9L 301ci V8
• 1978-1980 Pontiac Grand Am 4.9L 301ci V8
• 1978-1980 Pontiac Grand Prix 4.9L 301ci V8
• 1979-1979 Buick Century 4.9L 301ci V8
• 1979-1979 Buick Regal 4.9L 301ci V8
• 1979-1979 Oldsmobile Delta 88 4.9L 301ci V8
• 1979-1980 Buick Century 4.9L 301ci V8
• 1979-1980 Buick Regal 4.9L 301ci V8
• 1979-1980 Pontiac Catalina 4.9L 301ci V8
• 1979-1981 Pontiac Firebird 4.9L 301ci V8
• 1979-1981 Pontiac Grand LeMans 4.9L 301ci V8
• 1979-1981 Pontiac LeMans 4.9L 301ci V8
• 1980-1980 Buick Electra 4.9L 301ci V8
• 1980-1980 Buick Estate Wagon 4.9L 301ci V8
• 1980-1980 Buick LeSabre 4.9L 301ci V8
• 1980-1981 Buick Century 4.3L 265ci V8
• ...and 8 additional applications

Enginetech main bearings are engineered to OEM specifications, drawing on over 40 years of engine rebuilding expertise to deliver the precise clearance, crush, and eccentricity required for long-term durability under both stock and moderate-performance loads. Each set is application-specific: materials, wall thickness, oil clearance, and surface finish are all matched to the crankshaft main journal geometry and operating loads of the engine family it serves. Main bearings are a wear component and must be selected to match the crankshaft main journal size - bearings sized for standard journals will not seat correctly on undersize-machined journals and vice versa, so verify your journal measurement with a precision micrometer before ordering or installing. Always replace main bearings as a complete set. Mixing new bearings with used bearings produces uneven oil clearance across the crankshaft and accelerates wear on the freshly installed bearings - the small cost of a complete set is insurance against premature failure on the bearings you just paid to install. Enginetech documents every set with clear application-specific notes, journal-size designation, and cross-references so the right part lands on the bench the first time.

WARNING: This product can expose you to chemicals including likely lead/nickel — verify, which is known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information, go to www.P65Warnings.ca.gov.