Dart Machinery, LTD. stands behind each product we manufacture 100%. Each component undergoes a detailed manufacturing process that involves the hundreds of calculated and precision steps to ensure the finest quality possible.

Warning This product contains chemicals known to the State of California to cause cancer and reproductive harm. www.P65Warnings.ca.gov
PRO1 20 225cc CNC

PRO1 20° 225cc CNC

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Serious street performance, mild bracket racing and oval track. Maximum torque and throttle response from 3,500 to 7,800 RPM. Best for 363-427 cubic inch engines. Works with most standard components.

Every intake port, exhaust runner, valve bowl, and every combustion chamber is 100% CNC machined on special dedicated PRO1 castings. These heads are ideal for high compression, big cubic inch small blocks and are great for supercharged applications.

Exhaust runners are raised .135” for improved flow. Manganese Bronze valve guides are used for long life, and hardened valve seats provide durability with unleaded fuels. Features 3.000″ exhaust bolt pattern.

Assemblies include Stainless Steel valves, premium springs, locks, retainers, guide plates and seals.

Heads are sold individually.


Material: RMR Cast Aluminum Alloy

Valve Angle: 20° (stock)

Intake Port Volume: 225cc CNC

Intake Valve: 2.080”

Exhaust Valve: 1.600”

Chamber Volume: 62cc

PRO1 20° 225cc CNC – Aluminum

62cc Combustion Chambers

13072040 – Bare Head

13072142 – 1.437” Dual Springs for Hydraulic Roller or Solid Flat Tappet Cam .620”

13072143 – 1.550” Dual Springs for Solid Roller Cam .660”

PRO1 225 CNC Ford Tech Sheet – H33