{"product_id":"ls-main-crank-bearings-standard-size-si-series-precision-fit","title":"LS Main Crank Bearings Standard Size SI-Series - Precision Fit","description":"\u003cp\u003eOur review of these LS Main Crank Bearings finds them best suited to mechanics and enthusiasts rebuilding Gen 3 and Gen 4 LS engines who want a reliable, OEM-spec replacement without custom machining. The single biggest reason to buy is the precise, standard-size fit that restores correct oil clearance and smooth crankshaft rotation, making them a practical choice for both daily-driven vehicles and higher-load performance builds. The reviewer appreciated the durable tri-metal material and predictable compatibility across 4.8L to 6.2L LS variants.\u003c\/p\u003e\u003ch2\u003eKey Features\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrecision standard size:\u003c\/strong\u003e Manufactured to OEM specifications, these bearings restore proper oil clearance and reduce friction for reliable engine operation.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSI-Series material:\u003c\/strong\u003e Tri-metal construction provides improved heat dissipation and oil retention for longer bearing life under varied loads.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWide engine compatibility:\u003c\/strong\u003e Fits common Gen 3 and Gen 4 LS engines including 4.8L, 5.3L, 5.7L, 6.0L, and 6.2L, covering many stock and swapped applications.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStock and performance ready:\u003c\/strong\u003e Designed to handle increased loads from turbocharged or supercharged setups while maintaining factory-level precision.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDurability focus:\u003c\/strong\u003e Built for long-term reliability in daily drivers and high-horsepower builds where consistent oil flow is critical.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eWho It's For\u003c\/h2\u003e\u003cp\u003eThese bearings are aimed at technicians rebuilding OEM-spec LS engines and enthusiasts performing LS swaps who need a direct replacement that keeps crankshaft oil clearances within factory tolerances. The review recommends them for projects where maintaining factory dimensions is important rather than changing bearing size to compensate for shaft wear.\u003c\/p\u003e\u003cp\u003eThose who should look elsewhere include builders planning to increase or decrease bearing clearance intentionally for extreme performance or stroked cranks; custom-fit or undersize bearings would be a better match for shafts outside OEM tolerances.\u003c\/p\u003e\u003ch2\u003ePros \u0026amp; Cons\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003ePros\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eDirect OEM-size replacement simplifies installation and avoids machining when the crankshaft is within factory spec.\u003c\/li\u003e\n\u003cli\u003eTri-metal SI-Series construction offers good heat dissipation and oil retention for longer life under load.\u003c\/li\u003e\n\u003cli\u003eBroad LS engine fitment makes these bearings versatile for many rebuilds and swaps.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eCons\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\u003cli\u003eStandard size only, so a reground or worn crank may require undersize bearings instead of this set.\u003c\/li\u003e\u003c\/ul\u003e\u003ch2\u003eSpecifications\u003c\/h2\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003ctd\u003eBrand\u003c\/td\u003e\n\u003ctd\u003eMichigan Motorsports\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSeries\u003c\/td\u003e\n\u003ctd\u003eSI-Series\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSize\u003c\/td\u003e\n\u003ctd\u003eStandard size (OEM spec)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eConstruction\u003c\/td\u003e\n\u003ctd\u003eTri-metal bearing material\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatible engines\u003c\/td\u003e\n\u003ctd\u003eGen 3 \u0026amp; Gen 4 LS: 4.8L, 5.3L, 5.7L, 6.0L, 6.2L\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eApplications\u003c\/td\u003e\n\u003ctd\u003eStock rebuilds and performance builds\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003ch2\u003eOur Verdict\u003c\/h2\u003e\u003cp\u003eThese standard-size SI-Series main bearings are a solid value for anyone repairing or refreshing a factory-dimension LS crankshaft. They deliver dependable wear characteristics and heat management for daily drivers and many performance setups, but buyers with reground cranks or nonstandard clearances should choose matched undersize options instead.\u003c\/p\u003e\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eDo these bearings fit all LS engines?\u003c\/strong\u003e\u003cbr\u003eThey fit common Gen 3 and Gen 4 LS engines listed, including 4.8L through 6.2L, when the crankshaft is within OEM dimensions.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eAre these bearings suitable for forced induction builds?\u003c\/strong\u003e\u003cbr\u003eYes; the tri-metal SI-Series material is rated for increased load capacity seen in many turbocharged or supercharged setups.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat if my crank is worn?\u003c\/strong\u003e\u003cbr\u003eIf the crankshaft journals are out of spec or reground, undersize or matched bearings will be required instead of these standard-size bearings.\u003c\/p\u003e","brand":"Michigan Motorsports","offers":[{"title":"Default Title","offer_id":48751047999707,"sku":"B099KNX6Z3","price":59.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0724\/1043\/1707\/files\/71cbXljII6L._SL1500.jpg?v=1778773628","url":"https:\/\/gearmusthave.com\/products\/ls-main-crank-bearings-standard-size-si-series-precision-fit","provider":"GearMustHave","version":"1.0","type":"link"}