AFR 457cc BBC 18° 100% Fully CNC Ported Magnum Aluminum Cylinder Head 3708. This product data sheet is originally written in English. AFR Direct Master Warehouse Distributor – All AFR Products Available. AFR 457cc BBC 18° Magnum Cylinder Head. 950, 3-4 week build time. AFR’s new 457cc 18° Big Block Chevy heads are our best performing highest flowing head in our BB Chevy lineup. They come standard with stainless steel 2.400 intake valves and 1.800 exhaust valves. The intake port is raised. 500 with the valves rolled to 18° resulting in unparalleled under the curve flow numbers….. Don’t be fooled by just peak flow numbers. The combustion chamber comes in at 90cc. This head is ideal for 540CI or larger race engines. This head requires specific pistons, valves covers, shaft mount rockers and readily available intake manifolds. AFR offers a wide range of options and upgrades for this head like titanium valves and Copper seats. AFR head are available bare (without parts), call our tech line for details. AFR Part # 3708. There are many different options available for AFR heads, please view the details section below for the details on these heads. For the many other AFR heads available, and options such as upgrading springs or retainers. AFR Magnum 18 Degree 457 cc Big Block Chevy heads are the highest flowing head offering from AFR for Big Block Chevy engines. By having the intake ports raised. Along with the combination of moving the valves to 18 degrees, Magnum 18 degree cylinder head will flow a whopping 498 cfm of air through the intake ports at 1.000 in. Designed for 540 ci and larger racing engines, AFR offers Magnum 18 degree fully assembled, bare CNC ported, and bare unported casting for custom port work. 100% CNC Ported Intake Ports, Exhaust Ports, & Combustion Chamber. Competition 5-angle Valve Job. 11/32″ Bead Lock Stainless Steel Intake Valve, 2.400″ X 6.035 O. 11/32″ Bead Lock Stainless Steel Exhaust Valve, 1.800″ X 5.935 O. PAC Racing #1258 1.645 OD Solid Roller Triple Spring, 350 lbs. 950 maximum lift Max RPM 8300 to 8500. 10° 11/32 Bead Lock Valve Keepers with recess lashcaps. 11/32 Viton Valve Seals. Hardened Spring Cup 1.740 O. D X 1.677 I. 10° Titanium Retainer 1.500 O. D X1.180I. Exhaust Valve Seats 1.900 O. D X 1.400 I. Intake Valve Seats 2.450 O. D x 1.950 I. 11/32 Bronze Valve Guides. D X 2.700 O. 11/32 Exhaust Bronze Valve Guides. D x 2.25 O. We have AFR heads to fit almost every performance application! – UPS Worldwide Expedited – 3-9 days GUARANTEED! (Most Countries, check UPS. Com) – UPS Worldwide Saver – 1-5 days GUARANTEED! We do not lower invoice values since it is a violation of US and International custom laws. TREperformance 1725 Monrovia Ave. Suite D7 Costa Mesa, CA 92627.