AC Delco PF52 & PF47

[Drew99GT]

Is anyone 100% sure these two filters have no bypass valve? Also, has anyone cut one open to check for cardboard endcaps or lousy construction? I'm thinking I'll go with a PF-52 for 5,000 mile Mobil 1 10w-30 Supersyn drain intervals. I was going to go with a mobil 1 filter, but it seems they may be a bit too restrictive, especially for longer intervals?

 

[Drew99GT]

One more question. If these two filters do not have bypass valves, since most if not all late model GMs have an internal bypass valve, do other filter manufacturers use bypass valves in their equivalent filters to the 47 and 52?