If your truck is powered by an LML Duramax or 6.7L Cummins, you could replace ... the CP4 with the older CP3 pump. Instead, it has parts to reroute the fuel return lines through an additional ...
This gave the P-pump fueling advantages over earlier models. Other changes to the Cummins to meet the emission standards included redesigned pistons with a narrowed ring land and a new fuel bowl ...