Well now for all you syn oil buffs. I have a 1984 chevy 3/4 ton van with 378,000 miles. Everything is original in the engine and Transmission. I change oil (not syn) every 2500 miles. and filter also. It uses 1/2 quart between changes and is driven every day 2 1/2 miles to work and 2 1/2 miles back home, rain, snow or shine. The valve covers or any other cover has never been off. The transmission has been serviced every 20,000 miles and still works great. Granted the body is ready to fall off, but the ebgine is going strong on Regular OIL. Two more cents....