EC CNC Ported Big Valve 32/25mm Head using the Tillotson JT-207 Cylinder Head. 

We have built a 32/25mm valve combination cylinder head based on popular demand. Engine Builders and racers have found that the peak torque is at lower rpm with a smaller exhaust valve that improves low-end torque, leading to better acceleration for engines built for low-speed corners on short ovals or sprint kart racing or drag racing setups. 

The Head Comes with 32mm Intake and 25mm Exhaust Valves; 5mm Stems. Precision Multi-Angle Job, Valve Bowl area, cleaned up match to the seats. The valve work is performed on Rotter Seat & Guide Machine for accuracy and precision. Heads are vacuum checked after the valves are installed to ensure your air-fuel mixture and combustion happen in the cylinder. The Heads were Milled to ~18cc Combustion Chamber. The Cylinder Head is CNC Ported on our state heart multi-axis HAAS Machines. CNC porting rather than hand porting makes each port job consistent and accurate from head to head. CNC Machining also reduces the cost of labor to make it more budget-friendly. 

Head Specs:

– Intake: 32mm, 5mm

– Exhaust: 25mm, 5mm

– Combustion Chamber: 18cc, Non-Hemi

– Multi-Angle Valve Job

– CNC Ported

– Titanium Retainers

– Dual Valve Springs Installed at .975 at 46lbs Close Seat Pressure, .575 at 115lbs Open Seat Pressure, .535 Coil Bind

– Max Lift .400-inch (Examples .308 + 1.3 Ratio Rockers, .335 + 1.2 Ratio Rockers .356 + 1.1 Ratio Rockers)

Compression Ratio Examples(Final Result will vary on Engine Measurements):

Predator Hemi, Flat Top, .035″ Deck height,

w/.045″ Thick Head Gasket 9.22:1

w/.010″ Thin Head Gasket 10.48

Tillotson 212, Flat Top, .000″ Deck height,

w/.045″ Thick Head Gasket 10.48:1

w/.010″ Thin Head Gasket 12.19:1

Tillotson 225, Flat Top, .000″ Deck height,

w/.045″ Thick Head Gasket 10.87:1

w/.032″ EC Copper Head Gasket 11.49:1

EC 228R, Flat Top, .000″ Deck height,

w/.045″ Thick Head Gasket 11:01:1

w/.032″ EC Copper Head Gasket 11.63:1

EC 236R, Flat Top, .000″ Deck height,

w/.045″ Thick Head Gasket 11:37:1

w/.032″ EC Copper Head Gasket 12.01:1