FYI, after years of not recommending synthetic oil and even saying it would void the warranty if you run it, Harley Davidson did a 180 and now recommends synthetic and even runs it in their new engines, since about 2005/6, from the factory. They even sell synthetic oil under their own brand name at the dealerships. As I said, I've been running Mobil 1 it in my hog since it had 10K miles. I fully agree that our older style classic car engines should be broken in with dino oil for the first 5-10K miles before switching to synthetic. One more comment, if synthetic is too slick and doesn't provide the protection that dino oil does, then why do most of your NASCAR and professional drag racers run it in their $100K engines? Bottom line, synthetic provides better protection against heat, and doesn't break down as fast under heat and pressure. Once again, read the numeorus comparison lab tests on the internet.
