GM Performance Cylinder Head, Vortec, Cast Iron, Assembled, 64cc Chamber, 170cc Intake Runner, Chevy, Small Block, Each (PART #GMP-12558060)

GM Performance cast iron Vortec cylinder heads will fit 1958 and later small block Chevy engines, and offer a 20 to 40 hp increase over earlier cast iron small block heads. Features include fast burn combustion chambers, and a high-velocity port design. They require the use of a Vortec-style intake and self-aligning rocker arms, and come complete with valves, springs, and retainers.

SPECIFICATIONS
Brand GM Performance
Manufacturer's Part Number 12558060
Part Type Cylinder Heads
Product Line GM Performance Vortec Cylinder Heads
Combustion Chamber Volume (cc) 64
Intake Runner Volume (cc) 170cc
Cylinder Head Style Assembled
Cylinder Head Material Cast iron
Intake Port Shape Rectangular
Intake Valve Diameter (in.) 1.940 in.
CNC-Machined Combustion Chamber No
CNC-Machined Intake Runner No
CNC-Machined Exhaust Runner No
Intake Port Location Standard
Exhaust Port Shape Square
Exhaust Port Location Standard
Spark Plug Style Straight
Intake Valves Included Yes
Exhaust Valves Included Yes
Exhaust Valve Diameter (in.) 1.500 in.
Valve Springs Included Yes
Maximum Valve Lift (in.) 0.475 in.
Outside Diameter of Outer Spring (in.) 1.250 in.
Damper Spring Included No
Number of Springs Per Valve Single
Retainers Included Yes
Retainer Material Steel
Locks Included Yes
Lock Style 7 degree
Valve Stem Seals Included Yes
Valve Stem Seal Style Umbrella
Rocker Arm Studs Included Yes
Rocker Arm Nut Thread Size 3/8 in.-24
Rocker Arms Included No
Rocker Arm Nuts Included No
Guideplates Included No
Accessory Bolt Holes Drilled Yes
Valve Guides Included Yes
Valve Seats Machined Yes
Valve Seat Material Steel
Cylinder Head Color Natural
Steam Holes Drilled No
Oiling Style Through pushrod
Machined for O-Ring No
Heat Crossover No
Remanufactured No
Quantity Sold individually.
Notes Requires Vortec-style intake manifold for installation.

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