{"product_id":"cast-iron-s-b-chev-engine-block-4-125-bore-9-025-deck-height-400-mains-4-bolt","title":"Cast Iron S\/B Chev Engine Block, 4.125\" Bore 9.025\" Deck Height 400 Mains 4 Bolt","description":"\u003cdiv\u003e\n\u003ch2\u003eCast Iron S\/B Chev Engine Block, 4.125\" Bore, 9.025\" Deck Height, 400 Mains, 4 Bolt\u003c\/h2\u003e\n\u003cp\u003eElevate your small-block Chevy build with a robust, semi-finished foundation designed for serious street and performance use. Cast from premium Class 32B iron, this block delivers exceptional strength while minimizing machining. Its Siamese cylinder bores, splayed billet steel four-bolt main caps, and a priority main oiling pathway work together to keep bearings fed under demanding conditions. Built to seal reliably with standard off-the-shelf components, it’s the ideal starting point for a high-performance street build.\u003c\/p\u003e \u003ch3\u003eKey features\u003c\/h3\u003e\n\u003cul\u003e \u003cli\u003eSiamese cylinder bore design for compact, race-ready blocks\u003c\/li\u003e \u003cli\u003eBillet steel, four-bolt main caps with a splayed design for added hold-down strength\u003c\/li\u003e \u003cli\u003eMain Priority Oiling system (can be paired with dry sump) for dependable oiling under load\u003c\/li\u003e \u003cli\u003eThick deck height enhances head gasket sealing and accommodates common, off-the-shelf components\u003c\/li\u003e \u003cli\u003eCompatibility with standard camshafts, timing chains\/gears, and oiling systems to minimize bespoke machining\u003c\/li\u003e \u003cli\u003ePremium cast iron (Class 32B) and name-brand engineering designed for street and performance builds\u003c\/li\u003e \u003cli\u003eFinish-machining required by qualified machinists; factory tolerances apply and may be adjusted for your components\u003c\/li\u003e\n\u003c\/ul\u003e \u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003cul\u003e \u003cli\u003eBore: 4.125 in (max bore: 4.185 in)\u003c\/li\u003e \u003cli\u003eStroke: 4.000 in\u003c\/li\u003e \u003cli\u003eDeck height: 9.025 in; Deck thickness: 0.675 in\u003c\/li\u003e \u003cli\u003eCylinder wall thickness: 0.275 in (min at 4.185 in bore)\u003c\/li\u003e \u003cli\u003eCam journal OD: 1.869 in (STD)\u003c\/li\u003e \u003cli\u003eCam plug: 2.375 in press-in cup\u003c\/li\u003e \u003cli\u003eLifter bores: 0.842 in\u003c\/li\u003e \u003cli\u003eMain bearing size: 2.650 in (400); Main bearing bore: 2.849 in (400)\u003c\/li\u003e \u003cli\u003eMain caps: Billet steel, 3 center caps; 4-bolt splayed design\u003c\/li\u003e \u003cli\u003eMain cap bolts: 7\/16 in \u0026amp; 3\/8 in on Caps 1 \u0026amp; 5; 7\/16 in on Caps 2, 3 \u0026amp; 4 (splayed)\u003c\/li\u003e \u003cli\u003eMain cap register: Deep stepped (no dowels required)\u003c\/li\u003e \u003cli\u003eOil system: Main Priority Oiling (can use dry sump)\u003c\/li\u003e \u003cli\u003eOil pump shaft: 350.481 in\u003c\/li\u003e \u003cli\u003eOil filter: STD; Uses 2-bolt adapter\u003c\/li\u003e \u003cli\u003eOil pan: STD 350\u003c\/li\u003e \u003cli\u003eRear main seal: STD 400 2-piece\u003c\/li\u003e \u003cli\u003e2-piece serial number location: Left front \u0026amp; main caps\u003c\/li\u003e \u003cli\u003eStarter: STD\u003c\/li\u003e \u003cli\u003eStud holes, head: Blind holes\u003c\/li\u003e \u003cli\u003eTiming chain\/gears: STD\u003c\/li\u003e \u003cli\u003eTiming cover: STD\u003c\/li\u003e \u003cli\u003eWeight: 92 kg (205 lbs)\u003c\/li\u003e\n\u003c\/ul\u003e \u003ch3\u003eWhy builders choose this block\u003c\/h3\u003e\n\u003cul\u003e \u003cli\u003eProvides a robust, semi-finished foundation that minimizes machining while delivering durability for high-performance combinations.\u003c\/li\u003e \u003cli\u003eThe combination of Siamese bores, 4-bolt splayed main caps, and priority oiling helps maintain reliability under aggressive street performance and track usage.\u003c\/li\u003e \u003cli\u003eExtra-thick deck height supports dependable head gasket sealing and broad component compatibility with off-the-shelf parts.\u003c\/li\u003e \u003cli\u003eDesigned to work with standard street components, reducing bespoke machining while still allowing precise clearance and tolerances when finished by a qualified machinist.\u003c\/li\u003e\n\u003c\/ul\u003e \u003ch3\u003eMachining \u0026amp; assembly guidance\u003c\/h3\u003e\n\u003cp\u003eThis block is intended to be finished by a professional machinist. Expect factory tolerances that may require adjustment for your specific components. Key guidance includes:\u003c\/p\u003e\n\u003cul\u003e \u003cli\u003eDeburr cam bearing OD before installation; when removing main caps, de-burr both caps and block to maintain correct bearing sizes.\u003c\/li\u003e \u003cli\u003eCylinder bores may require honing and pistons may need width\/skirt clearance adjustments; oversized pistons are common and require appropriate skirt clearance.\u003c\/li\u003e \u003cli\u003eVery few aftermarket components drop in without additional checking and machining—verify all tolerances and clearances with a qualified machinist for reliable performance.\u003c\/li\u003e \u003cli\u003eEnsure head gasket sealing and oiling pathways align with your chosen components; consider compatibility with a dry sump system if desired.\u003c\/li\u003e\n\u003c\/ul\u003e \u003ch3\u003eApplications\u003c\/h3\u003e\n\u003cp\u003eIdeal for serious street-performance builds where strength, oiling efficiency, and compatibility with off-the-shelf parts matter most. This block offers a solid, proven platform for modern small-block Chevy combinations, balancing rugged cast-iron durability with practical assembly considerations for reliable, long-term operation.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"TGM Performance Parts","offers":[{"title":"Default Title","offer_id":47472193208490,"sku":"AF96-1001","price":2722.9,"currency_code":"AUD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0658\/7829\/4698\/files\/AF96-1001.jpg?v=1759126255","url":"https:\/\/tgmperformance.com.au\/products\/cast-iron-s-b-chev-engine-block-4-125-bore-9-025-deck-height-400-mains-4-bolt","provider":"TGM Performance Parts","version":"1.0","type":"link"}