The venerable 5.9l 6BT is considered the small block Chevy of the diesel performance world! This power-plant has been used, abused, changed, rearranged, engineered and tuned to performance perfection, including a class of old shade tree git-r done style of Racing! This power-plant will out last the truck it was meant for! True Performance Diesel knows the Cummins. FYI if you have the 3.9l 4BT you can use some of the same performance parts as its 6 cylinder brother! And dont forget the 6BT P-pump, and the newest genration of cummins i-6. The ISB, ISB CR, and  the B6.7. To the Exclusive Cummins Community! We strive to have all the necessary means for you to build your engine the way you want IT!