John Kaase Racing Engines Has entered the street performance market with their new P51 aluminum cylinder heads for Ford 429/460 big-block engines, the 385 series. Earlier this decade, Kaase demonstrated their considerable engine-design talents when they corrected longstanding failings in the original 385 series cylinder heads.
The engine’s potential was finally realized when Kaase relocated the valves, redesigned the combustion chambers, and reconfigured the internals of the intake and exhaust ports. For the first time, the 385 series engine exceeded the 350-cfm peak intake flow of the desirable Boss 429. Kaase with Ford designated the new heads the Super Cobra Jet.
Commendably, Kaase retained the 72 cc combustion chambers, which allow users to run pump fuel. This chamber size also permits experimentation with different compression ratios: employing slightly dished or slightly domed pistons as desired. Importantly, the P51 chambers are fully CNC-machined, and contain larger 2.250-inch intake valves. The standard size exhaust valves are retained. The P51 heads function with the original rocker gear, but require longer pushrods because of altered valve geometry. For convenience, intake and exhaust port locations are unchanged. Contact Jon Kaase Racing Engines (770) 307-0241 www.jonkaaseracingengines.com