We are officially an authorized dealer of Diesel Spec Inc. These world leaders of ECM tuning technology know how to get big power and fuel savings out of your big rig NAPC is your source for Transmissions, Differentials, Torque Converters, Transfer Cases, Engines, Bearing Kits, Hard Parts and more. We provide a variety of applications and custom builds for your Dodge, Ford and GM/CHEV truck. more... See more text