Here are the specs for the head.

Material: A356-T61 aluminum
Combustion Chamber Volume: 78cc CNC-profiled
Intake Port Volume: 240cc CNC Street Ported
Intake Port Location: Stock
Intake Port Dimensions: 2.270" x 1.230"
Intake Valve Diameter: 2.190"
Intake Valve Seat: Ductile iron
Exhaust Port Volume: 74cc CNC Street Ported
Exhaust Port Location: Stock
Exhaust Port Dimensions: 1.250" x 1.650" oval
Exhaust Valve Diameter: 1.760"
Exhaust Valve Seat: Ductile iron
Valve Angles: 15°
Valve Guide Material: Bronze alloy
Valve Seals: Viton® fluoroelastomer canister
Valve Seat Angles: 45° x multi-angle
Valve Spring Pocket Diameter: 1.615"
Valve Spring I.D. Locators: 1.300"
Valve Spring Retainers: Steel or titanium
Valve Stem Locks: 7° or 10° steel
Valve Springs, Standard: 1.460" o.d. dual spring with damper
120 lbs. @ 1.900" installed height
394 lbs. @ 1.175" open
390 lbs. per inch rate
.650" max. valve lift
Valve Springs, Option 1: 1.550" o.d. dual spring
138 lbs. @ 1.950" installed height
430 lbs. @ 1.250" open
420 lbs. per inch rate
.680" max. valve lift
Valve Springs, Option 2: 1.560" o.d. dual spring with damper
240 lbs. @ 2.000" installed height
600 lbs. @ 1.280" open
500 lbs. per inch rate
.700" max. valve lift
Rocker Arms: Roller rocker arms recommended