What about acdelco oil filters and the napa golds? I use ac and at one time the pf56 had a drain valve and now it doesn't. They are much better quality than the Fram. Thicker paper, etc. The napa goods are very heavy duty. I used to work for them and I compared. Good, heavy quality and thick filtering media. How do they stack up? Steve '84 5ksT 1.8 bar