I run Rot. 15w-40 in everything but my new tractor which I run their 5w-40 full syn. I ran it in my 800 cu. in. Cummins OTR truck. No additives, just oil. Worked fine for me. I'd buy it in the 55 gallon drums too. My big cam took 11 gallons per change and i had to change it about every month due to mileage.
Delo, Rot, Exxon XD3, etc. All have the starburst "compression" rating. Not being negative, but what difference does the number of cylinders make?