CobraEd, when I first read your post, I thought you meant Royal Purple scored towards the bottom, and I was surprised. Pleased to see I misunderstood your meaning. I've been using Royal Purple for 20,000 miles in my 496 Chevy and have no intention of changing. I'd put 5,000 miles on the engine, using non-
synthetic Castrol, before going with RP and have not had any of the rumored leakage, other than the normal Chebby marking its territory. Thanks for posting the link to the test results.