<P> A natural - gas - powered engine debuted for 1995 but was not popular and was only used in fleet vehicles on a very limited production run . The Cummins B Series engine was switched from the 12 - valve to the 24 - valve ( ISB ) version in the middle of the 1998 model - year Dodge Rams due to emissions regulations . The ISB featured a new computer - controlled injection pump , 24 - valve head design , and an electric fuel pump . </P>
<P> A natural - gas - powered engine debuted for 1995 but was not popular and was only used in fleet vehicles on a very limited production run . The Cummins B Series engine was switched from the 12 - valve to the 24 - valve ( ISB ) version in the middle of the 1998 model - year Dodge Rams due to emissions regulations . The ISB featured a new computer - controlled injection pump , 24 - valve head design , and an electric fuel pump . </P>
when did dodge go to the 24 valve
when did dodge go to the 24 valve
in the middle of the 1998 model - year
in the middle of the 1998 model - year