Choose older models of cylinder heads over the modern ones if you intend to increase power output from your engine. Newer cylinder heads have thinner metal sections and have an increased mixture velocity favoring those who are more mindful of the vehicle mileage over power.
Select modern casting cylinder heads for racing vehicles. However, you may choose to have cylinder heads specially cast for your engine combining all the qualities and functionality you are looking for. Some companies produce different types of cylinder heads made of aluminum that deliver improved performance in engines.
Inspect carefully a cylinder head bought from a used vehicle parts store. Since cylinder heads are made of cast iron, they are prone to break and fracture during use, therefore those found in used parts stores may as well be damaged.
Decide on a cylinder head that fits within your budget. If the one specially suited for your vehicle engine is unaffordable to you, resort to using older models of cast cylinder heads and in time improve on several of its aspects such as port flow and valve size. This requires you save up for these upgrades although the ultimate cost surpasses what you would spend on a newer model head.
Choose a cylinder head with a small port volume but with better flow. An example is that of a 190 cc port volume head with flow velocity comparable to that of a 220cc port volume head. Smaller heads are preferred because they contribute to increased torque in the engine.