{"product_id":"stage-5-cnc-ported-heads-with-b25-castings","title":"Stage 5 CNC Ported Heads with B25 Castings","description":"The IAG Stage 5 CNC Ported Chamber Matched Heads feature a comprehensive CNC porting program for B25 heads, refined over five years and tested on successful high-horsepower Subarus. These heads begin with new B25 OEM castings sourced from Subaru of America (compatible with 2004-06 STI, 2004-05 Forester XT, and 2005-06 Legacy GT models). The bare castings are meticulously fixtured into a Centroid 5-axis CNC machine for precise porting of intake and exhaust runners, ensuring consistent results.\n\nFurther enhancements include a combustion chamber modification to match STI head shapes and a cam clearance process to prevent contact with large duration cam profiles. The heads are drilled for larger 1\/2\" or 14mm head studs to increase clamping force. OEM valve guides are replaced with Ferrea Copper\/Bronze guides for improved heat dissipation and lubricity. These guides are diamond-honed, and the intake and exhaust seats are cut with a multi-angle valve job to optimize flow for the included Ferrea Comp Plus +1mm valves. The decks are resurfaced for a smooth finish, and the heads are ultrasonically cleaned before reassembly with Ferrea Dual Valve Springs, Titanium Retainers, and valve stem seals.\n\nCams and lifters are sold separately. This product is not legal for sale or use in C.A.R.B. restricted areas.","brand":"IAG","offers":[{"title":"Default Title","offer_id":52688779149624,"sku":"IAG-ENG-3050SC","price":5999.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0970\/4895\/3144\/files\/662669693.webp?v=1784895717","url":"https:\/\/store.motormia.co\/products\/stage-5-cnc-ported-heads-with-b25-castings","provider":"MOTORMIA","version":"1.0","type":"link"}