River City Diesel Thumper HPOP UpgradeThumper I High Pressure Oil Pump. The Thumper I works great from stock up to 225CC injectors. This pump comes with a One Year Warranty. This pump netted and additional 100rwhp* over a new stock pump at 3000 RPM with 225CC upgraded Injectors. This is the ultimate drop in upgrade for a 2005-2010 6.0 Powerstroke, and will out perform any pump on the market.