I can see a low mileage engine in a larger truck. Some of them really didn't get used much, but probably spent a lot of time idling too. I think I would still use 10w-30 or 30w in the chevy small blocks. A heavier oil may mask a noise problem slightly, but doesn't solve the problem.
I think you are on the right track and I'd start with readjusting the lifters and go from there. Get a cheap stethescope for listening to your engine. You will hear the before and after sound when you make the adjustments. You will remember that sound and use that information down the road too.
Last edited by Builder; 05/19/2009 5:49 PM.
