[westofb]

I prefer valvoline in all my motors, someone mentioned that pennzoil was a good oil....I strongly disagree. I have rebuilt many SB chevy engines over the years, when tearing one down for a rebuild it was not hard to tell the ones that had been using pennzoil, the amount of sludge in those motors is incredible. I have seen them so bad that the valve covers were completely packed with sludge, only enough room left in there for the valve train componets to move. Maybe alot of it was caused by poor maintainance, maybe just the nature of the beast, I am not sure, but I chose not to use it from my past experiences with it. However, if you have one that has been running pennzoil, I recommend to keep using until it gets rebuilt, if you switch to another brand, that has more detergent additives in it, it will break loose alot of that sludge and possibly cause an engine failure.

I imagine that alot of the problems I have seen are mostly due to neglect, however, I have never disassembled a motor using valvoline that had much more than minor deposits in it, in fact most were extremely clean inside.