The 5.9L ISB (Interact System B) is one of the largest straight-6 engine ever produced for passenger vehicles, and the improved high output 600 version was on the Ward's 10 Best Engines list for 2004. One unusual feature of the ISB is that it is a multi-valve pushrod engine design. The engine displaces 5883cc with a 102.1mm bore and 119.9mm stroke. A turbocharger output in the high-compression (17.2:1 in recent versions) Diesel. It is an all-iron engine with forged steel connecting rods, an assembled camshaft, and a cast aluminum intake manifold. The engine is produced in Columbus, Indiana. There have been several versions of the 5.9 L ISB featured in the Dodge Ram. The B5.9 was first introduced to Dodge Rams in 1989. The Cummins engine in 1991 got an intercooler. In 1994, the engine changed over to a Bosch model P7100 inline-style injection pump from the previous Bosch VE series rotary pump. Midway through model year 1998, the engine which would now be known as the ISB, was redesigned as a 24 valve model to meet updated emissions requirements and introduced the Bosch VP44 rotary injection pump (featuring electronic control) to the Dodge application. It produced 235hp (175kW) at 2700rpm and 460ft·lbf (625Nm) from 1600rpm to 2700rpm when paired with a manual transmission, but was slightly downrated when used with automatics. In 2001, an optional high output (HO) version of the ISB was introduced, producing 245hp (183kW) at 2700rpm and 505ft·lbf (686Nm) from 1600rpm to 2700rpm when paired with a heavy duty six-speed transmission, the NV5600. The ISB from previous years remained available, and automatic-equipped engines were now rated the same as manuals.