OLD OIL: I have been selling and using oil from a closed oil company dated from the mid 80's to early 90's. I have had no problems and the farmers keep coming back for more. This oil works better in my 50's & 60's Chevy motors than the new oils. Many owners of older cars using new oil are having their cams go flat because the new oils lack friction lubrication. And they are having to use racing oils in their older engines to meet the friction needs and the racing oil prices are much higher.
Just look at the API Service Code to make sure it is ok top use with your engines. I was told that you should use API SL or lower code oil for NON roller tappet & cam engines.