If you need the worlds finest street/strip small block Ford head, check out AFR's all new 185cc intake port emissions legal (CARB EO #250-3) cylinder heads. With 2.020 intake valves, 1.600 exhaust valves, combustion chamber volumes of 58cc or 72cc, and 69cc exhaust ports, AFR's new 185cc Ford head is 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. Will not accept rail rocker arms. Hardened pushrods required with 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. Ford Small Block - 185cc CNC Street Ported Heads - 72cc Combustion Chambers, Stud Mount Rockers - Fully Assembled