3-4 week build time. AFR Part Number #1840. AFRs 260cc LS3 Mongoose heads are the ultimate rectangular port for the LS3 and L99 engines. They feature 100% CNC ported intake, exhaust and chambers using our advanced engineering and flow techniques to produce the ultimate Rectangle Port head available today. Featuring A356 aluminum castings, titanium retainers and the highest quality components, throughout. Theyre designed for 4.000 or larger bore applications up to 454 CI, operating up to 7000 RPM. Emmisons legal for 2008 to 2015 vehicles under CARB #D-250-5. Component upgrade and machining options are available to customize AFR Heads to your specific build. The Ultimate Bolt-On Emission Legal Street/Strip Weapon! 260cc Aluminum LS1 Cylinder Heads. CNC Ported w/parts 6 Bolts. CNC Ported w/parts 4 Bolts. 260cc Street Head Flow Chart. 100% CNC Ported Combustion Chambers 100% CNC Ported Exhaust Ports 100% CNC Ported Intake Ports Competition 5-angle. 8mm Bead Lock Intake Valve, 2.165″ x 5.195″ Overall Valve Length. 8mm Bead Lock Exhaust Valve, 1.600″ x 5.200″ Overall Valve Length. PAC Racing Spring 1.270 OD Hydraulic Roller Dual Valve Spring, 155 lbs. 7° Titanium Retainers 1.245 O. 7° Bead Lock Valve Keepers. Hardened Valve Spring O. D Locator 1.380 O. Ductile Iron Intake Valve Seats 2.200 O. D x 1.750 I. Ductile Iron Exhaust Valve Seats 1.650 O. D x 1.350 I. 8 mm Bronze Valve Guides. D x 2.550 O. Specifications, Features, and Optional Supporting Components. Factory GM or Aftermarket. Cometic 4.160 Bore Size. Head Bolt Washers, Manley. FAST 92mm, or 102mm. Spark Plug Starting Range. 2.610″H x 1.300″W x 7/16° Radius. 1.540″ H x 1.760″ W. Valve Cover Bolt Pattern. Valve Spring Pocket Diameter. Max Valve Spring Pocket Machining. Flat Mill – 65cc chamber. 006 per cc 62cc Maximum. Minimum Cross Sectional Area. AFR LS3 – General Recommendations for AFR Cylinder Heads. Pushrods – Different length pushrods might be required, always check pushrod length. Check pushrod clearance with heads placed on the block before final assembly. Larger pushrods will not fit without clearancing and is not recommended since some areas are very thin. AFR recommends the use of. Mills – Flat or angle mills could affect flow numbers and might require a thicker intake gasket. Stud Girdles – Due to many available factory OEM and aftermarket style/variations your existing stud girdle may not fit (AFR heads require AFR Stud Girdles). Boosted/Nitrous Applications – We strongly recommend considering Inconel exhaust valves and AFR’s optional heavy duty intake valve for power adder applications. Since boosted or nitrous oxide applications accelerate RPM quickly, additional spring pressure is required. We strongly recommend upgrading your valve springs or increasing your valve spring pressures since boost pressure on the valve reduces spring tension. For example, 15lbs boost on a 2.125 OD valve reduces the springs closed seat pressure by approximately 40-45lbs. All MARINE Applications – We strongly recommend Inconel exhaust valves & also offer a hard anodized coating to slow the effects of corrosion. Please see note on guide clearance below. Valve Guide Clearance – Your AFR Heads come with proper guide clearance. 0012″. 0016″ for most applications. Boosted/Nitrous or marine applications might require additional clearance and it is the customer’s responsibility to verify proper clearance in these applications. Valve Springs – Forced induction, nitrous oxide and cams with aggressive ramp rates may require additional spring pressure. We offer optional valve springs for these types of applications. AFR also recommends the use of billet cam cores and short travel Hydraulic Roller lifters which tolerate higher spring loads. AFR Titanium Valves – Might require lash caps and different length pushrods. Titanium valves are coated, do not grind valves because it removes the protective coating. Piston to Valve – AFR assumes no responsibility for damage if the end user builds an engine without properly verifying he has enough piston to valve clearance (depth and radial clearance both checked). We recommend a minimum depth of. 080 on the intake valve and. 100 on the exhaust with a radial clearance of. 020 minimum around the perimeter of each valve. Clay is recommended to visually verify both depth as well as radial clearance. Just checking depth is not enough, the position of the valve pocket must also be addressed. It is the customers responsibility to verify proper piston to valve clearance. CNC Porting – Occasionally a 100% CNC ported head might have a very small area left “as cast”, this in no way affects performance. Shaft Mount Rockers – Shaft mount rockers might require additional clearance for proper pushrod fitment. Do not clearance the push rod area as the wall is. Spring Installation – To ease installation with 1.550 O. D or larger springs, 12 pt head bolt or studs are recommended for extra clearance. D and doesn’t need to be ground. Rocker Arms – Use full roller rocker arms, roller tip rockers with stock style bodies are NOT recommended. Important: Do not port match you intake manifold to any Fel-Pro gasket as it does not precisely match AFR heads. Note: Milling head deck will affect flow numbers. We do not lower invoice values since it is a violation of US and International custom laws. Let us work to resolve your problem so everyone is happy. TREperformance 1725 Monrovia Ave. Suite D7 Costa Mesa, CA 92627. The item “AFR 260cc 100% CNC Ported LS3 Aluminum Cylinder Heads 6 Bolt Mongoose. 650 Lift” is in sale since Monday, June 12, 2017. This item is in the category “eBay Motors\Parts & Accessories\Car & Truck Parts\Engines & Components\Cylinder Heads & Parts”. The seller is “treperformance” and is located in Costa Mesa, California. This item can be shipped worldwide.

• Placement on Vehicle: Front
• Part Brand: Air Flow Research
• Interchange Part Number: Airflow
• Brand: Air Flow Research
• Warranty: Yes
• Country/Region of Manufacture: United States
• Core Charge: None
• Material: Aluminum
• Manufacturer Part Number: AFR 1840
• Fitment Type: Performance/Custom