Dynamic Racing - 14.6:1 High Compression Piston Kit Substantial performance increase over the stock piston. Piston works well with pump fuel and race fuels! Pump Fuel, T4, Pro6, MR12 or equivalent are all safe to use with the stock ECU. However for maximum performance, we recommend using this with our Vortex ECU and custom tuned maps. Includes: -14.6:1 JE Piston (Custom under-crown milling to work with the beefy Carrillo rod) -DLC Coated Wrist Pin -OEM Rings -Circlips