Fans of the Dodge Ram Cummings platform frequently discuss generation 1 and generation 2 body styles. These discussions spill over to the classic 12 valve vs. 24 valve engines debate. There are actually several overlapping elements to this discussion and this article seeks to provide timeline clarity.

Body Styles
The Generation 1 body style was produced from 1983 to 1993. In 1989 Dodge incorporated a B Series Cummins diesel platform into Generation 1 trucks. In 1994 Dodge rolled out its long awaited Generation 2 body style and continued to offer the Cummins B Series platform.
Cylinder Heads
Dodge incorporated B Series Cummins engines with two different cylinder heads. Dodge Ram trucks from 1989 to 1998.5 featured a 12 valve cylinder head. In 1998.5 the platform switched to a 24 valve cylinder head.
Injection Pumps
Between 1989 and 2001, Dodge Rams equipped with B-Series Cummins engines featured 3 different mechanical fuel pumps. Diesel trucks manufactured between 1989 and 1993 featured Bosch VE injection pumps. Those manufactured between 1994 and 1998.5 rolled off the assembly line with the infamous Bosch P7100 injection pump. In 1998.5, in conjunction with the introduction of the 24 valve cylinder head, the VP44 pump was incorporated into the platform. The VP44 was the first computer over mechanical design which relied on a computer system control timing and other parameters of the mechanical pump.
Common Questions
Dodge shipped generation 1 style trucks from 1981 to 1993? (source: Wikipedia)
Dodge shipped generation 1 style trucks from 1993 to 2001? (source: Wikipedia)
Dodge Ram’s manufactured between 1989 through 1998.5 featured an optional 12 valve 5.9L Cummins engine. (Source: CarThrottle)
Dodge offered a diesel power plant in generation 1 trucks from 1989 to 1993. (source: DrivingLine)
Generation 2 Dodge Ram’s featured 12 valve Cummins turbo diesel engines from 1993 to 1998.5. In 1998.5, Dodge introduced 24 valve cylinder heads to meet increasing emission requirements. (source: DrivingLine)
Generation 2 Dodge Ram’s featured 24 valve Cummins turbo diesel engines from 1998.5 to 2001. (source: CumminsHub)
From 1993 to 1998.5 5.9L Cummins powered Dodge’s shipped with P7100 or “P Pump” injection pumps. (source: DrivingLine)
The VP44 injection pump was shipped in 24 valve Cummins turbo diesels from 1998.5 through 2001. (source: DrivingLine)
The last truly mechanical injection pump, the P7100, was phased out in 1998.5 when it was replaced with the electronic over mechanical VP44 pump. (source: Jalopnik)