{"product_id":"mangum-racing-275cc-11-degree-ls3-cylinder-heads","title":"Mangum Racing 275cc 11-Degree LS3 Cylinder Heads","description":"\u003cp\u003eThe MR275 is a maximum-effort 11° LS3 cylinder head built around a Mangum Racing 6-bolt casting with a .750\" deck surface. Revised valve locations, a 275cc CNC intake runner, and a 98cc exhaust port are engineered for airflow, piston-to-valve clearance, and durability in high-compression or high-cylinder-pressure combinations.\u003c\/p\u003e\u003ch3\u003eKey Features\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e6-bolt Mangum Racing 11° LS3 casting with .750\" deck thickness\u003c\/li\u003e\n\u003cli\u003eOptimized valve locations with 275cc CNC intake ports and 98cc exhaust ports\u003c\/li\u003e\n\u003cli\u003e70.5cc fully CNC-machined combustion chambers\u003c\/li\u003e\n\u003cli\u003e2.185\" hollow-stem stainless extended-length intake valves and 1.600\" stainless extended-length exhaust valves\u003c\/li\u003e\n\u003cli\u003eChoice of PAC 1207X, 1208X, or 1209X dual springs with titanium retainers\u003c\/li\u003e\n\u003cli\u003eBronze guides, Viton seals, 1.250\" steel spring seats, and minimum 4.000\" bore\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eAirflow Performance\u003c\/h3\u003e\u003cp\u003eSuperFlow data with a 4.125\" bore plate; intake uses a radius entry and exhaust is tested without a pipe.\u003c\/p\u003e\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eValve Lift\u003c\/th\u003e\n\u003cth\u003e.200\u003c\/th\u003e\n\u003cth\u003e.300\u003c\/th\u003e\n\u003cth\u003e.400\u003c\/th\u003e\n\u003cth\u003e.500\u003c\/th\u003e\n\u003cth\u003e.600\u003c\/th\u003e\n\u003cth\u003e.700\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eIntake CFM\u003c\/th\u003e\n\u003ctd\u003e143\u003c\/td\u003e\n\u003ctd\u003e221\u003c\/td\u003e\n\u003ctd\u003e283\u003c\/td\u003e\n\u003ctd\u003e330\u003c\/td\u003e\n\u003ctd\u003e358\u003c\/td\u003e\n\u003ctd\u003e381\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eExhaust CFM\u003c\/th\u003e\n\u003ctd\u003e112\u003c\/td\u003e\n\u003ctd\u003e161\u003c\/td\u003e\n\u003ctd\u003e202\u003c\/td\u003e\n\u003ctd\u003e232\u003c\/td\u003e\n\u003ctd\u003e242\u003c\/td\u003e\n\u003ctd\u003e248\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003cp\u003e\u003cstrong\u003eInstallation note:\u003c\/strong\u003e Extended-length valvetrain components require careful pushrod, rocker, and piston-to-valve clearance checks.\u003c\/p\u003e","brand":"Mangum Racing","offers":[{"title":"Default Title","offer_id":54111766479167,"sku":"MR-27511DLS3","price":2899.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0760\/2041\/6831\/files\/mangum-racing-mr-27511dls3_22199c35-160f-49f6-afd4-952f4225beb5.webp?v=1784146868","url":"https:\/\/smgspeed.com\/products\/mangum-racing-275cc-11-degree-ls3-cylinder-heads","provider":"SMGspeed","version":"1.0","type":"link"}