With Edelbrock's ongoing development of performance parts for Mopar applications, it was only a matter of time before they introduced a cylinder head for these engines. The most outstanding feature of the Edelbrock heads in comparison to the production units is an improvement in airflow of better than 25 percent. Peak intake flow, given by Edelbrock at 260 cfm, puts the new Magnums among the better stock-style aftermarket heads for any competitive small-block engine type. The heads are cast at Edelbrock's foundry in A356 aluminum alloy and heat-treated to T-6 specifications. With that, we have the second outstanding feature of these heads: a weight savings of some 40-plus pounds for the set.
Beyond the flow and materials are Edelbrock's quality control and finishing. Edelbrock castings are some of the best in the industry in casting core consistency for uniform thickness in critical areas of the port wall and water jackets. The head castings are fitted with the quality components you'd expect from a performance cylinder head, including stainless steel valves measuring 2.02-inches intake and 1.60-inches exhaust. The valves feature 11/32-inch stems, helping reduce critical valve weight, which are retained by high-performance springs with 125 pounds of seat load, and quality steel retainers and locks. The valvespring installed height of 1.975 inches and compact valveguide bosses lend a much higher lift capacity than the OE setup. All of this means the heads are setup as delivered for high-performance use.
Edelbrock's Magnum heads are configured for aftermarket roller rockers, with 3/8-inch studs that receive rocker arms designed to fit the common small-block Chevy application. This interchangeability allows for a wide range of rocker choices at low-ball Chevy prices. To complete the valvetrain, the heads are equipped with steel guide plates, which need to be used with hardened pushrods. As with all Magnum engines, the pushrods must be hollow with open ends for oil to flow to the rockers.
 As with the intake port, this...  As with the intake port, this cut-away view of the exhaust port leaves little to be critical of. The entire port is a nice sweep from the chamber to the exit, without the ugly roof kink, flat floor, and irregularities of the factory's stock old LA-style heads. Also note the ample water jacket areas and thick deck. |
 With the larger ports, thicker...  With the larger ports, thicker walls, and other Edelbrock modifications, the Edelbrock Magnums have a more closed architecture than factory stock heads. Drainback becomes an issue and is addressed with special drain-back drillings at strategic locations adjacent to the ports. |
 One of the Magnum's best features...  One of the Magnum's best features is the compact 58cc combustion chamber with ample quench areas at each end. This allows a quicker burn for more efficient combustion and excellent detonation tolerance. Valves measure 2.02-inches intake and 1.60-inches exhaust, a proven combination for high-performance street small-blocks. We would expect to find a flow gain from chamber machining adjacent to the valves to further reduce shrouding. |