They’re great out of the box in “as cast” form. With 235cc intake runners they’ll provide ample flow to keep up with the camshaft/intake combinations of most larger displacement small block Chevy engines.
For those who desire optimum performance, World Products offers these heads CNC-ported.
With 250cc intake runners and enlarged, 90cc exhaust ports. The CNC ported heads also boast a larger 2.100” Manley stainless steel intake valves, so you can readily see the kind of power these designs (developed by Kuntz & Company) will deliver.
TECHNICAL SPECS
Casting ID Number: WOR-077A
Material: 355-T6 alloy high density aluminum
Valve Seats: Intake (hardened), exhaust (hardened)
Valve Guides: Manganese bronze
Spring Seats: Machined for 1.560"
Valves: Manley stainless steel valves in assemblies
Valve Diameter: 2.080" intake, 1.600" exhaust (11/32" stem) as cast, 2.100" intake, 1.600" exhaust (11/32" stem) CNC ported
Guide Plates: Stock (Special guide plates required for 235cc head, part #830456)
Rocker Arm Studs: Screw-in style
Rocker Arms: 1.5 offset ratio (use of 1.6 ratio may require elongation of pushrod holes)
Intake Runner: 235cc, standard port location
Exhaust Ports: 70cc standard location
Combustion Chamber: 64cc, angled plug orientation
Spark Plug: 14mm .750" reach gasket style
Valve Job: Multi-angle intake and radiused exhaust
Valve Cover Rail: Raised w/ perimeter and center bolt pattern
Valve Angle: Stock 23°
Accessory Bolt Holes: Stock
Spring Specs
1.250": 100 lbs. @ 1.810", 300 lbs. @ 1.250", coil bind @ 1.200", max lift @ .570"
1.437": 125 lbs. @ 1.810", 340 lbs. @ 1.210", coil bind @ 1.160", max lift @ .600"
1.550": 200 lbs. @ 1.900", 480 lbs. @ 1.200", coil bind @ 1.150", max lift @ .700"
Head Flow @ .800 Lift
286 intake, 204 exhaust (Super Flow 1050)
304 intake, 219 exhaust (Super Flow 600)
CNC Ported Head @ .800 Lift
306 intake, 220 exhaust (Super Flow 1050)
329 intake, 238 exhaust (Super Flow 600)
All heads flowed with a standard .750" intake plate, without exhaust tube, and 28" of water.
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