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.

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PRO1 15 250cc LS CNC

PRO1 15° 250cc LS CNC (LS1 compatible)



Recommended for engines with 4.000” bore or larger. Maximum competition, competition modified drag racing, circle track. Over 7,000 RPM.

Dart’s PRO1 15° 250cc LS CNC ported Aluminum cathedral port cylinder heads for GM LS series small block V8 engines take performance to the next level.

This LS CNC cathedral port head is machined on a dedicated casting with extra thick sections to maintain the proper wall thickness after porting. Due to the large diameter intake valves, the Dart LS CNC head is recommended for use on engines with 4.000 inch and larger cylinder bores. Precise computer controlled CNC machining, multi-angle intake seats, and radiused exhaust seats enhance airflow. Extra material above the ports accommodates valve train upgrades.

Heads are sold individually.


Material: RMR Cast Aluminum Alloy

Valve Angle: 15° (stock)

Intake Port Volume: 250cc CNC

Intake Valve: 2.080”

Exhaust Valve: 1.600”

Chamber Volume: 68cc

11071040 – Bare Head 2.080/1.600 VJ

11071142 – 1.290” Beehive Springs for Hydraulic Roller 2.080/1.600 .625”

11071143 – 1.295” Dual Springs for Hydraulic Roller 2.080/1.600 .650”

LS1 CNC Head Tech Sheet – H59