i used 10w-40 in my 74 nova for a while and kept getting low oil pressures at idle after the engine warmed up. i also kept getting metallic particles on my magnetic oil drain plug (its a 350 with 10k on it now). i switched to straight 40 weight and the oil pressure is substaintially better at idle and more consistent throughout the rpm range. i haven't pulled the drain plug yet, but i have a feeling its not going to look as bad.
am i mistaken, or do i just not need a multi-weight oil in houston? it never freezes here anymore, and it gets pretty warm. would my fram oil filter have anything to do with this (which i'm not using anymore, since i noticed the filter element had come loose inside!)?