This Chevrolet Performance Small Block Chevy "Fast Burn" Aluminum Cylinder Head has the highest performance potential of any 23° small block head developed by Chevrolet using flat top pistons. It adds 30 bolt-on horsepower when used on the Chevy ZZ4 crate engine. 62cc fast burn combustion chambers produce higher cylinder pressures by burning more of the available fuel before the piston starts its power stroke downward. Head surfaces and rocker rails are CNC-machined to exact tolerances, thus eliminating the need for blueprinting. D-shaped ports and runners require no additional porting (but can be for all-out racing applications). This cylinder head fits 1958-Present small block Chevy 283-400 engines with a conventional water flow design (cannot be used on LT1, LT4, or LS1 engine with reverse water flow). The cylinder head is completely assembled with valves, springs, retainers, and 3/8'' rocker studs that require the use of self-aligning rocker arms.
Intake Runner: 210cc Port raised .240''
Exhaust Runner: 78cc ''D'' Port raised .200''
Combustion Chamber Volume: 62cc
Deck: .400'' thick (Can be milled)
Valve Diameter: 2.00'' Intake, 1.55'' Exhaust
Valve Spring Seat: 1.48''
Valve Springs: .530'' Maximum Valve Lift
Rocker Studs: 3/8'' Top, 7/16'' Bottom
Spark Plugs: Angled, 5/8'' Hex, 3/4'' Reach, Tapered Seat
Dual Intake Bolt Pattern for Vortec (recommended) and Early Intakes
Dual Valve Cover Bolt Pattern for Perimeter or Centerbolt
JEGS Easy Kits are designed by JEGS professionals to ensure that you get all the correct parts you need.