Once you are done with cam break-in, change the oil. After the 500-mile ring-seating break-in, change the oil again. For both break-in cycles we used the Comp Cams break-in additive and regular non-synthetic oil. Once past that, we switched it over to Royal Purple 10W-30 and a Royal Purple oil filter (PN 30-8A). The bigger filter gives us an extra half-quart or so of oil, not to mention that much more filtering media inside the can itself.