{"product_id":"edelbrock-sb-oldsmobile-performer-rpm-cylinder-heads-for-hydraulic-flat-tappet","title":"Edelbrock SB Oldsmobile Performer RPM Cylinder Heads for Hydraulic Flat Tappet","description":"Intended for installation on 1965-1976 Small-Block Oldsmobile 350-403 c.i. engines equipped with a flat tappet camshaft, these 356-T6 aluminum casting cylinder heads (PN61039) are a modern refinement to our PN6051 heads, except they can accommodate a factory-style mechanical fuel pump. A smaller 68 cc combustion chamber achieves a more appropriate small block compression ratio compared to our PN61025\/61029’s larger 77 cc chamber, which yields a lower compression ratio than most engine builders desire on a small block engine. These heads require a 3.9375” minimum bore and feature a modern chamber design with optimized spark plug positioning. Maximum airflow is achieved through the factory 6-degree valve angle using high-flow 200 cc intake and 130 cc exhaust port volumes, along with 2.072” intake and 1.680” exhaust valve sizes in their O.E. positions. A finished deck thickness with added material above the intake port and pre-counterbored head-bolt holes for .5” diameter studs provide extra clamping force in key areas. A stud-and-guide plate valvetrain system (as opposed to the O.E. pedestal type) provides a solid foundation for the beefier diameter pushrods, and Helicoil inserts in the exhaust and rocker stud holes keep bolts secured. However, there are no provisions for a heat crossover. Although these heads will fit on Big-Block Oldsmobile engines, the 68-cc combustion chamber size is not ideal for a big-block application as it will raise compression. See PN 61025 and PN 61029 for big-block specific cylinder heads.\u003cbr\u003e\u003ca href=\"https:\/\/d32vzsop7y1h3k.cloudfront.net\/6649f48ea5069c7f40600a0592be76ab.PDF\"\u003eInstallation Instructions\u003c\/a\u003e\u003cbr\u003e","brand":"Edelbrock","offers":[{"title":"Default Title","offer_id":47009088274653,"sku":"EDE61039","price":1305.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0590\/3758\/1491\/files\/25b0c4a30da398c73b4231e92ef0c4afL_326abf2a-5ead-4b79-8d10-8174a9eb3388.jpg?v=1763100199","url":"https:\/\/hellhoundperformance.store\/products\/edelbrock-sb-oldsmobile-performer-rpm-cylinder-heads-for-hydraulic-flat-tappet","provider":"Hellhound Performance","version":"1.0","type":"link"}