I changed the oil in both the 1987 Chevrolet G20 Sportvan and 1990 Buick Riviera today. They both went from 5W30 to 10/30 for the cold days. The odometer reading for the van is 149,834.5mi and the Rivi's is 126,132mi.
I finally installed my oil pressure gauge in the van. It's running between 30 - 40psi.