The Cummins ISC is a straight-6 diesel engine with 8.3 liters in displacement. The ISC went into production in March 1998. It was built off its predecessor, the C8.3 engine using the Interact System, which combined advanced electronic engine controls, high-pressure fuel injection and heavy-duty components. It improved power, fuel economy, reliability and durability. The Cummins ISC also has a sister engine which is designed off the existing 8.3 liter block which runs on compressed natural gas. This is the Cummins C8.3G.