Show me an old Chevy six that doesn't leak oil and I'll show you an old Chevy six that doesn't have oil in it.
BTW, as far as I know, at this time, the only straight 30 available in a full synthetic is Royal Purple. Lucas has a 30 wt, but I'm not sure if it's synthetic or not, thier site doesn't say one way or the other. I've priced it here, about $4.80 a qt.
