I work at Newell Coach Corp. and we make and service 1.5 million average motor homes. I am a service tech and have done many a p.m. using napa filters on Detroit series 60, Cat C-15, and now our newest motor a Cummings 650. The way I see it if our Coaches run napa stuff it should be ok to run then on a tractor. Look us up at Newellcoach.com