{"product_id":"advance-headers-mild-steel-exhaust-extractors-holden-hq-wb-253-308-v8-a412","title":"Advance Headers | Mild Steel Exhaust Extractors | Holden HQ-WB 253 308 V8 | A412","description":"\u003ch2\u003eAdvance Headers High-Performance Mild Steel Exhaust Extractors for Holden HQ to WB 253 \u0026amp; 308 V8 Engines\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eThe Advance Headers Performance Exhaust Extractors (A412) are classic heavy-duty tubular manifolds engineered explicitly for golden-era Australian GM Holden muscle cars and commercial utilities. Tailored to fit the legendary small-block Holden 253-Cubic Inch (4.2L) and 308-Cubic Inch (5.0L) red, blue, and black V8 powerplants, this kit spans a massive heritage vehicle lineage, including HQ, HJ, HX, HZ, and WB model series. By replacing the highly restrictive factory cast iron log manifolds, this mandrel-bent configuration significantly drops engine backpressure, optimizing gas scavenging velocity to unlock vital low-to-mid range torque and that unmistakable classic Aussie V8 rumble.\u003c\/strong\u003e\u003c\/p\u003e\n\u003cdiv class=\"feature-block\"\u003e\n\u003cdiv class=\"feature-content pb-6\"\u003e\n\u003ch3 style=\"color: #e60000; font-weight: bold;\"\u003e\u003cspan style=\"color: rgb(0, 0, 0);\"\u003ePRODUCT CONTENTS:\u003c\/span\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e1 x Heavy-Duty Mild Steel Left-Hand Holden V8 Extractor Header Assembly\u003c\/li\u003e\n\u003cli\u003e1 x Heavy-Duty Mild Steel Right-Hand Holden V8 Extractor Header Assembly\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eKey Features:\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eTuned mandrel-bent primary piping pathways ensure completely uniform internal flow geometry, optimizing exhaust scavenging velocity across daily driving and high-load towing bands\u003c\/li\u003e\n\u003cli\u003eSubstantially optimizes low-to-mid range torque delivery—ideal for improving throttle response, open-road cruising, and hauling loads in commercial utility setups\u003c\/li\u003e\n\u003cli\u003eHeavy-duty mild steel construction structurally built to handle intense under-bonnet thermal expansion cycles and typical classic V8 vibrations safely\u003c\/li\u003e\n\u003cli\u003eThick, precision laser-cut cylinder head flanges maintain a flat, ultra-stable mating footprint to permanently guard against warping, face distortion, and high-pressure gas leaks\u003c\/li\u003e\n\u003cli\u003eEngineered for a fast workshop turnaround, featuring an estimated baseline installation window of just 2 hours\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003e\u003cstrong\u003eSpecifications:\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cdiv class=\"specs\"\u003e\n\u003cul class=\"flex flex-col space-y-2 text-xs\"\u003e\n\u003cli\u003e\n\u003cspan class=\"text-gray-500 font-semibold mr-1\"\u003eBrand:\u003c\/span\u003e \u003cspan class=\"text-gray-700\"\u003eAdvance Headers\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"text-gray-500 font-semibold mr-1\"\u003ePart Number:\u003c\/span\u003e \u003cspan class=\"text-gray-700\"\u003eA412\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"text-gray-500 font-semibold mr-1\"\u003eMaterial:\u003c\/span\u003e \u003cspan class=\"text-gray-700\"\u003eMild Steel (Standard Finish)\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"text-gray-500 font-semibold mr-1\"\u003eEngine Suitability:\u003c\/span\u003e \u003cspan class=\"text-gray-700\"\u003eHolden 253ci (4.2L) \u0026amp; 308ci (5.0L) SOHC OHV V8 Petrol Engines Only\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"text-gray-500 font-semibold mr-1\"\u003eComponent Type:\u003c\/span\u003e \u003cspan class=\"text-gray-700\"\u003ePerformance Exhaust Extractors \/ Headers\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"text-gray-500 font-semibold mr-1\"\u003eEstimated Fitting Time:\u003c\/span\u003e \u003cspan class=\"text-gray-700\"\u003e2 Hours\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan class=\"text-gray-500 font-semibold mr-1\"\u003eWelding Required:\u003c\/span\u003e \u003cspan class=\"text-gray-700\"\u003eNo (Direct Bolt-On Configuration to Cylinder Heads)\u003c\/span\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003e⚠️ Crucial Transmission \u0026amp; Selector Linkage Fitment Alignment Warnings:\u003c\/strong\u003e\u003cbr\u003eThis product (Part No. \u003cstrong\u003eA412\u003c\/strong\u003e) is formed precisely to navigate the engine bay aprons, chassis rails, and crossmembers of the HQ-WB platform. However, \u003cstrong\u003eif you are fitting these extractors to a vehicle utilizing a Column-Shift Trimatic automatic transmission configuration, you must purchase and use the dedicated linkage adapter kit (Part Number: A412-Linkage)\u003c\/strong\u003e. Failure to adapt the selector node will result in physical interference between the shifting arm linkages and the primary exhaust pipes.\u003c\/p\u003e\n\u003cp\u003e\u003cem\u003ePlease Note: Professional installation by an exhaust specialist or qualified classic automotive mechanic is highly recommended to guarantee proper system alignment, selector clearance checkouts, and a perfect leak-free seal.\u003c\/em\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003ch2\u003eImportant Information\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eThe image shown may not reflect the actual product design.\u003c\/li\u003e\n\u003cli\u003eEnsure your vehicle details match the application guide below before purchasing.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cdiv style=\"font-family: Arial, sans-serif; max-width: 100%; padding: 20px; border: 1px solid #ccc; border-radius: 5px; font-size: 1rem;\" class=\"product-details-container\"\u003e\n\u003ch2\u003eVehicle Applications for A412 Performance Holden V8 Extractors\u003c\/h2\u003e\n\u003cdiv style=\"width: 100%; overflow-x: auto; -webkit-overflow-scrolling: touch; margin-bottom: 10px;\"\u003e\n\u003ctable style=\"min-width: 1100px; border-collapse: collapse; font-size: 1rem; line-height: 1.5; width: 100%;\"\u003e\n\u003cthead\u003e\n\u003ctr style=\"background-color: #f0f0f0; border-bottom: 3px solid #333;\"\u003e\n\u003cth style=\"padding: 10px 8px; text-align: left; border: 1px solid #ddd; white-space: nowrap;\"\u003eMake\u003c\/th\u003e\n\u003cth style=\"padding: 10px 8px; text-align: left; border: 1px solid #ddd; white-space: nowrap;\"\u003eModel\u003c\/th\u003e\n\u003cth style=\"padding: 10px 8px; text-align: left; border: 1px solid #ddd; white-space: nowrap;\"\u003eYear Range Spec\u003c\/th\u003e\n\u003cth style=\"padding: 10px 8px; text-align: left; border: 1px solid #ddd;\"\u003eBody Type\u003c\/th\u003e\n\u003cth style=\"padding: 10px 8px; text-align: left; border: 1px solid #ddd;\"\u003eChassis Series\u003c\/th\u003e\n\u003cth style=\"padding: 10px 8px; text-align: left; border: 1px solid #ddd;\"\u003eEngine Details\u003c\/th\u003e\n\u003cth style=\"padding: 10px 8px; text-align: left; border: 1px solid #ddd; white-space: nowrap;\"\u003eFitting Time\u003c\/th\u003e\n\u003cth style=\"padding: 10px 8px; text-align: left; border: 1px solid #ddd;\"\u003eDrivetrain \/ Fitment Notes\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px; border: 1px solid #ddd; white-space: nowrap; font-weight: bold;\"\u003eHolden\u003c\/td\u003e\n\u003ctd style=\"padding: 8px; border: 1px solid #ddd; white-space: nowrap; font-weight: bold;\"\u003eKingswood \/ Premier \/ Belmont \/ Monaro \/ Statesman\u003c\/td\u003e\n\u003ctd style=\"padding: 8px; border: 1px solid #ddd; white-space: nowrap;\"\u003e1971 – 1980\u003c\/td\u003e\n\u003ctd style=\"padding: 8px; border: 1px solid #ddd;\"\u003e4-Door Sedan \/ 2-Door Coupe \/ 5-Door Wagon \/ Ute \/ Panel Van\u003c\/td\u003e\n\u003ctd style=\"padding: 8px; border: 1px solid #ddd;\"\u003eHQ \/ HJ \/ HX \/ HZ Series\u003c\/td\u003e\n\u003ctd style=\"padding: 8px; border: 1px solid #ddd;\"\u003eHolden 253ci (4.2L) \u0026amp; 308ci (5.0L) V8 (Red \/ Blue Block Families)\u003c\/td\u003e\n\u003ctd style=\"padding: 8px; border: 1px solid #ddd; white-space: nowrap;\"\u003e2.0 Hours\u003c\/td\u003e\n\u003ctd style=\"padding: 8px; border: 1px solid #ddd;\"\u003eRWD | Mandrel-bent upgrade routing mapped to clear classic steering boxes and underbody structures. Fits floor-shift manual\/auto formats directly. Requires A412-Linkage kit for Column-Shift Trimatic versions.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"padding: 8px; border: 1px solid #ddd; white-space: nowrap; font-weight: bold;\"\u003eHolden\u003c\/td\u003e\n\u003ctd style=\"padding: 8px; border: 1px solid #ddd; white-space: nowrap; font-weight: bold;\"\u003eWB Series (Caprice \/ De Ville \/ Commercial)\u003c\/td\u003e\n\u003ctd style=\"padding: 8px; border: 1px solid #ddd; white-space: nowrap;\"\u003e1980 – 1985\u003c\/td\u003e\n\u003ctd style=\"padding: 8px; border: 1px solid #ddd;\"\u003eLong-Wheelbase Luxury Sedan \/ Utility (Ute) \/ One-Tonner Cab-Chassis \/ Panel Van\u003c\/td\u003e\n\u003ctd style=\"padding: 8px; border: 1px solid #ddd;\"\u003eWB Series Only\u003c\/td\u003e\n\u003ctd style=\"padding: 8px; border: 1px solid #ddd;\"\u003eHolden 253ci (4.2L) \u0026amp; 308ci (5.0L) V8 (Blue \/ Black Block Families)\u003c\/td\u003e\n\u003ctd style=\"padding: 8px; border: 1px solid #ddd; white-space: nowrap;\"\u003e2.0 Hours\u003c\/td\u003e\n\u003ctd style=\"padding: 8px; border: 1px solid #ddd;\"\u003eRWD | Heavy-duty configuration fits commercial applications and luxury cruisers cleanly. Check column-shift mechanism clearances prior to torque-down phases.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003ch2\u003ePayment \u0026amp; Security\u003c\/h2\u003e\n\u003cp\u003eYour payment information is processed securely. We do not store credit card details nor have access to your credit card information.\u003c\/p\u003e","brand":"Advance Headers","offers":[{"title":"Default Title","offer_id":53765141889297,"sku":"A412","price":819.0,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0144\/8787\/9766\/files\/Advance_Headers_Mild_Steel_Exhaust_Extractors_Nissan_Pintara_U12_Ford_Corsair_2.4L_KA24E_A476_744ad6d2-ea07-4490-8d66-daec32241c4c.png?v=1784086450","url":"https:\/\/www.exhaustshop.com.au\/products\/advance-headers-mild-steel-exhaust-extractors-holden-hq-wb-253-308-v8-a412","provider":"Exhaust Shop Australia","version":"1.0","type":"link"}