The first picture is an engine from a 2001 Pontiac Grand Prix 3800, 197,000 miles. As far as I know it has always had conventional motor oil in it. Notice the gunk build up. This is an engine from a 1995 Oldsmobile Eighty-Eight 3800m 134,000mi, my grandfather's car. Exact same engine as the Grand Prix. I just got this car a week ago. Anyways, he has always used Amsoil Synthetic motor oil in it. Notice how much cleaner it is? I believe the oil was changed about every 7,500 or 10,000 miles, I'll have to double check his note tonight. This is why I use Amsoil Synthetic oil in my vehicles.