MMR M4000R Racing Pistons The ultimate Modular piston has arrived! The MMR M2500R pistons are the only production piston track and dyno proven to handle up to 3000 RWHP in a modular application. No other Modular piston manufacturer can claim this or back it up! Over 5 years of research and development with MMR and Manley engineers along with testing by our MMR Pro-Mod, Outlaw and Extreme Drag Radial team bring you the finest piston ever for your 4.6 or 5.4 or 2011-2021 5.0 Modular application. * Designed for Street and Race use * Proven and tested by team MMR up to 4000RWHP!!! * E85 Compatible * MMR RED FIRE Dome Coating * Full Banded Skirt for increased Piston Stability * 1000hp Chrommoly Piston Pin comes std. (upgrades offered below) * Thickest Ring lands in the industry while still maintaining low emissions. * Anti detonation groove standard * 5.4/5.8 Specific design available with ZERO deck. * Longest lasting and quietest pistons available. * All compression ratios and bore sizes (have a custom need - call us)