Cummins engines were dominant in agriculture long before their debut in heavy-duty trucks. The 12-valve 5.9-liter Cummins I-6 engine was developed and installed in Dodge pickups starting in 1989 ...

Among engine manufacturers, Cummins is ... engine started with 12 valves, but later generations saw improvements such as the addition of an intercooler, a switch to a 24-valve configuration ...