If you need the world's finest street/strip small block Ford head, check out AFR's all new 185cc intake port emissions legal performance cylinder heads. With lightweight 8mm 2.020 intake valves, 1.600 exhaust valves, combustion chamber volumes of 58cc or 72cc, and 70cc exhaust ports, AFR's new 185cc Ford cylinder heads are designed for 302-351 cid engines operating from 1500 rpm to 6500 rpm. A 3/4" thick head deck makes the AFR head ideal for nitrous or blower applications. Available with optional nitrous or blower exhaust port featuring 70cc ultra high flowing exhaust ports. Will not accept rail rocker arms. Hardened pushrods required with cylinder heads #1420 and #1422. High flow 2.020 valves might require aftermarket pistons notched for valve clearance. Note: 1986 5.0L must have pistons notched for clearance.