Piston design impacts how the ignition flame travels, the quality of airflow, fuel distribution, and more. The style you choose is usually based on valve clearance and compression requirements.
Flat Top Pistons
This piston has a flat top. It is typically used in mass-produced engines. It is easy to manufacture, which keeps the cost low.
Dished Pistons
This piston has a bowl- or dish-shaped top. It is used to reduce Compression Ratio because it adds volume to the chamber. It can be used in turbocharged or supercharged engines to help avoid Detonation. It makes for a fast-burning, compact combustion chamber.
Domed Pistons
This piston has a dome-shaped top. It reduces the chamber volume and increases Compression Ratio. However, it can create slow-burning, inefficient combustion chambers.
Valve Reliefs
Valve reliefs can be added to any style piston. They are also called "trenches" or "cups." The reliefs are areas where small amounts of material have been removed.
The purpose of the relief is to increase Piston to Valve Clearance. The added clearance allows for more camshaft Lift and Duration. Any valve relief will also affect the Piston Head Volume.