Fits: 2001 Thru 2010 Chevy Silverado/GMC Sierra 2500HD/3500HD LB7/LLY/LBZ/LMM Duramax Diesel This Brand New LBZ based S&S 12mm Stroker Pump(46% over stock displacement) is the best option for any customer needing to get more power and flow out of a single CP3 set up. The 12mm Stroker Pump will out perform and outlast any other pump on the market. They are set up to support over 1000hp with 1 single CP3. The 12mm pump is modified to eliminate the fuel flow restrictions that begin at 3000 RPM on stock CP3's. This pump can also be used in a LML CP3 conversion(tuning may be required). Notes: Brand New Pump (No Core Needed) Tuning is REQUIRED if installing on 2001-2005 LB7 and LLY engines Fitment on LB7's requires you to modify the regulator connectors to make them fit. THE MANUFACTURE, SALE, OFFER FOR SALE, OR INSTALLATION OF THIS PRODUCT IS NOT LEGAL IN CALIFORNIA.