AFR 227cc intake port small block Chevy angle plug aluminum cylinder heads are available in two stages of performance. The Race Ready version features 100% CNC ported intakes while the higher flowing Competition version features 100% CNC ported intakes with greater detail. Both come with 100% CNC ported 65cc or 75cc combustion chambers and 80cc exhaust ports with a 3/4'' thick head deck (ideal for nitrous or blower applications). Standard valves are lightweight 8mm diameter stem, 2.100'' intake and 1.600'' exhaust with AFR's hardened ductile iron interlocking valve seats. The 227 has 60/40 valve spacing and piston valve pockets should be checked. The exceptional flow characteristics and 23° valve angle make this the perfect head for 350-434ci engines in drag cars, sprint cars, and late model oval trackers operating from 4500 rpm and up. If you choose to run stud girdles AFR offset girdles are required. These heads requires shaft mount rockers or .050'' offset rocker arms for durability and reliability of valve train components. With the .050'' offset the intake rocker arm will be at a slight angle and the roller tip will not be perfectly parallel or centered on the valve tip. Not recommended for street use, unless shaft mount rocker is used. The exhaust port and bolt pattern are raised .250'' over GM L-98 cylinder head, this rarely affects header or chassis fitment. These 227cc aluminum cyilnder heads are available in either standard port or spread port exhaust configurations. Spread port heads have the center exhaust ports spread apart 5/8'' over stock L98 GM heads. The reason for spread port heads is to achieve additional cooling in the center of the head where the heat concentration is greatest. As standard headers do not fit, spread port headers are required since the center ports are spread further apart then stock GM products. The increased spacing on the exhaust port also requires the use of exhaust gasket Fel-Pro p/n 375-1409. Spread port heads only come with a Stahl bolt pattern. AFR's spread port head has all the benefits and features of AFR's standard head. Made in USA.
For over thirty years Airflow Research has been defining technological leadership in cylinder head manufacturing and flow dynamics.
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