That's the way to break in a cam. If you don't pre-oil the new engine. fire it up to idle speed until you get good oil pressure, look for any leaks, then run it at 2000rpm for 20 min or more. 30w is not as "thick" as you think. after your break in period, drain the oil and put in what you want. I would also buy an anti drainback filter (from Napa) that will help build oil pressure faster on cold start's. One would want to change the oil after break-in anyway to get rid of any break-in junk the filter catches on initial startup.