ALUM3251212.300/1.8801.55

Dart Pro 1 Marine Cylinder Heads feature a highly efficient chamber with improved fuel distribution, optimized spark plug location, and five-angle intake seats from wet flow research. They have a special hard chromate surface treatment for corrosion/erosion resistance, are cast from premium 355-T61 aerospace alloy, and include Inconel exhaust valves. They offer bolt-on compatibility, a 2-degree rolled valve angle, and standard spacing for stock accessories. Available in four intake port sizes (275cc oval, 310cc, 325cc, 345cc rectangle), these heads have 121cc heart-shaped chambers for improved combustion efficiency. Raised spark plug location and multi-angle intake/radiused exhaust seats boost airflow. Hardened exhaust seats are unleaded-compatible. Exhaust ports are raised .300" (requiring 1" longer lead bolts). Spark plug holes are machined for gasketed 3/4" reach plugs. Manganese bronze valve guides extend life. As-cast heads are bowl blended on 5-axis CNC machines.