Sealed Power builds engine bearings using materials and alloys engineered for demanding applications. We tailor our bearings to withstand punishing racing conditions. Our bearings are proven winners in NHRA, NASCAR® and IHRA competition. Sealed Power engine bearings include a patented contoured-flange design that increases thrust-load capacity and a three-quarter-length oil groove that enhances lubricity without compromising load capacity. The materials in Sealed Power bearings offer a variety of advantages, such as high durability, corrosion resistance, decreased rate of wear and increased fatigue strength. These advantages are all essential features for performance engines that need to withstand punishing racing conditions. Our DUROSHIELD® Competition Series Coated Bearings provide protection against dry starts and conditions that interrupt oil supply. Sealed Power's H-14 Super Duty Alloy has the greatest load-carrying capacity. Our H-24 Alloy is notable for its desirable fatigue resistance and strength. Our B100 babbitt material is used in ultra-high-performance rod and main bearings for blown-fuel and alcohol engines that require high "embeddability" and conformability.Pit Stop USA offers Sealed Power Competition Series Main Bearing Set - SB Chevy 302, 305, 307, 350 - 3/4 Groove - .030" Undersize 139M30 at low everyday prices. Be sure to check out all of our products from Sealed Power including Sealed Power Sealed Power Main Bearings - Small Block Chevy.