My suggestion is to try the "blow" test on any filter before you put it on the car. The anti-drainback valve shoud keep you from blowing air throught the filter. Just blow through the center hole. Air on your cheeks means the valve failed.
And yes, it may get you strange looks in the parts store or even end in a discussion with the store personnel.
I checked a lot of things when I made the "Biggie" and that valve turned out to be a major item. I don't consider Fram, knowing how they are built. The first Mobile One I tried in the store failed, more AC's failed than not. I had an AC engineer tell me it was because the seal needed to be wet with oil to work properly, but the ones that leaked also had knock. Wix, and their NAPA clones, are nice filters, but one of my first users took the time to pull his filter after the car sat and found the filter to be about 1/2 empty. He had knock.
The most consistant filters I found were the Purolators and I went with the PL20033 for the "Biggie" kits because I couldn't find a better filter for the price and I liked the idea it was the same filter used on the 455. The PureOne has gone out of stock in the larger size and when my stock is gone I will go with a standard L20033.
For the none "Biggie" folks, Lisa's 93 Regal uses the PF52 sized filters and I put the PureOne PL24011 on it. Those are still in stock. My Silver 6 87T is still all original with over 200K on Castrol GTX and Lisa has just gone over 175K. Good filters and good oil, and lots of changes.
