no they came on light trucks. i believe the 21's came on the non intercooled engines

Turbo2332 is correct. Not an industrial application but to my knowledge all the 88-93 VE pump Cummins trucks. I have seen a few with 18cm and I was told they were on the intercooled manual trans 4wd trucks from 91.5-93. They didn't work worth a damn with either 18 or 21 on the manual trans trucks however. My friends 93 D250 with the manual trans had 4.10's stock and literally didn't get over 10lbs of boost until he changed out his exhaust housing.

Jeff