Just as stated above. Fram builds the top part of their filters out of cardboard. Now, in a high oil pressure engine, the cardboard can collapse and shut off all oil flow to your motor.... Now I don't have to tell you how bad that can potentially be to your motor.
This is why people don't like Fram oil filters for their mustangs.
i heard from someone a while ago that you shouldnt use synthetic oil with motorcraft oil filters, but i dont know how true that is. i always use motorcraft personally.
I've always used the puralator "pure one" filters. I've heard nothing but good about them. I'm sure there are better ones, i've herad mobil1 is really good.
Fram = ****. I put one on my 83 (before knowing 2 sh its about anything) and the oil pressure literally dropped 20 PSI. I changed it back to a Motorcraft RIGHT away. That's ALL I run. If it's good enough to come with it, it's good enough to run it all the time.
The Motorcraft filter is justabout the best you can get if you take quality, performance, and price all into consideration. I've used the expensive ones before, and have never seen a test that flat out says they're better -- but I have seen tests that say Motorcraft is as good as the high-dollar ones.
This is the best study I've seen on oil filters. It will change the way you think. Also interesting to us because the study uses the 5.0 filter as subject of the study: http://www.scuderiaciriani.com/rx7/oil_filter_study/
I have never run anything but Fram and Motocraft, except on my C5 which I have not changed the oil on yet. 95 % of the time I use Fram. I travel about 70,000 miles a year and have NEVER seen a problem with any of my oil filters. I'm not saying the claims in this thread are invalid, just that I have never had a problem with mine. I will continue to use them.
WLDHRSE - read the detail of the study (I think someone linked it above too - http://www.scuderiaciriani.com/rx7/oil_filter_study/ ) - if you do, I believe you'll likely change your filter choices. I disassembled several filters lots of years ago - stopped using Fram at that time. Purolator or Motorcraft are MUCH better choices than Fram for comparable $.
I've been extremely pleased with every Mobil 1 product I've ever used. Spend the extra $. My car is as old as I am, I think an 11 dollar oil filter is worth it.