• Made from lightweight A356 aluminum, heat treated to T-6 spec for maximum strength
• Powerful design combustion chambers and exhaust heat crossover passage for emissions equipment compatibility
• Ends of cylinder heads have accessory bolt bosses for compatibility with stock bracketry
• Fully CNC machined, all bolts holes have Heli-Coils for strength
• 50-state street legal (E.O. #D-215-46)

• Complete assemblies include one-piece stainless steel valves, intake 2.19"and exhaust 1.88". 1.54" valve springs to handle valve lifts up to .700", steel retainers, keepers, 7/16" studs, 3/8" guide plates, bronze guides, and umbrella seals
• Deck surface is designed for both Mark IV and Gen V blocks
• Oval port heads made 520 HP and 470 ft/lbs. on the dyno!

BB Chevy 396-454-502 Mark IV, Performer RPM Heads 454-O, 110cc chamber, 290cc intake port, Valve Sizes (in/ex)-2.19"/1.88" Oval Port, Assembled

110cc, 454-O Oval Port

110cc, 454-O Oval Port H.P.