Beyond functioning as head casting, combustion chamber, and valve holder, cylinder heads play a big role in determining the engine breathing properties as well as the overall engine personality for racing cars. Many people simply go for specific brand names when buying cylinder heads. For a select population, however, going for customized cylinder heads is the only option when you want peak performance or when the available known brands do not specifically have your engine's type. Whichever category you fall in, the process of selecting the right cylinder heads for your engines must always be governed by your intended venue of use for your car. While bigger may seem better, this is not always the case. It is important to note that certain cylinder heads may be the best for your friend's engine, but not necessarily suitable for your engine or venue. The following are some venue characteristics and the corresponding cylinder head specifications you may want to look out for.
An engine designed primarily for street racing may spend a good duration of time between idle and part throttle. Such an engine, therefore, requires a good response when it comes to low and mid-range torque as well as throttle. Heavy automatic cars will require this more due to the weight. To keep air velocity high, you will therefore need cylinder heads that have moderately high runner volume intake. You should also consider the peak valve lifts. These should not be exceedingly high. A set of heads with moderate airflow at moderate valve lifts is your ideal option for the right amount of torque and horsepower.
Drag engines will probably spend a considerable but short duration at full throttle. During these instances, you will need maximum valve lift and high airflow at high rotations per minute from your engine. If your engine has the appropriate induction system and boosts pressure, large cylinder heads would be the ideal option. The large heads would provide maximum airflow and valve sizes appropriate for this type of punctuated high-performance venue.
Circle track engines
Many circle tracks have specific rules governing the type of cylinder heads used on engines. Some tracks only allow cast iron heads while others specify depth and valve angles. Generally, good circle track cylinder heads are those that deliver average to high rotations per minute throttle reaction as well as torque at the bends. This, however, entirely depends on the driver's style.
Whichever your venue, trust a good cylinder heads provider to help you make choices on intake runner volumes, valve sizes, valve angles, combustion volumes and many other specifics with regard to your intended venue.