Inspired by Dart's championship winning Pro Stock designs, Dart Pro 1 aluminum cylinder heads cover a wide range of applications from street cars and trucks to all-out racing. Heads designed for street performance and mild bracket racing offer excellent mid-range torque and power, and are excellent for heavier vehicles. Competition heads are ideal for maximum effort naturally aspirated, big boost forced induction, or nitrous applications. Dart Marine Pro 1 cylinder heads feature an exclusive chromate surface finish to inhibit corrosion and extend the life of the head. They are also fitted with Inconel exhaust valves to withstand the extended running time and temperatures typical of marine usage. Dart's as-cast ports flow more than many ported designs at a much more affordable price. But they also offer fully CNC-machined heads with every intake port, exhaust runner, valve bowl, and combustion chamber shaped by their 5-axis, computer controlled machining centers to produce compound curves and complex shapes that no human could duplicate with a hand grinder. Available bare or fully assembled, long-wearing bronze valve guides, screw-in studs, multi-angle intake seats with hardened, radiused exhaust seats are standard on most heads. Assemblies typically include stainless steel valves, premium springs, locks, retainers, guide plates, and seals. Many Pro 1 heads include race-proven features such as improved spark plug location, extra-long intake valves, raised exhaust ports, and fast burn chambers. They are offered an extensive variety of valve angles, intake port volumes and shapes, exhaust port locations, valve sizes, and chamber volumes.