There was a post on this some time back and I can't find it. Oil types are a particular choice for different people based on their experience or just plain product preference. Which is better in a 500 hp BBC (6000rpm) for just high speed driving alone. Single weight or multi-weight? How about break in on a fresh motor.....single weight for the first 20 minute run-in, then multi-weight? Any good rules of thumb?! What are you using and what is your experience. Thanks for the reply