I thought this may help in selecting the oil filter you feel most comfortable with. The quote below comes from Hastings tech support when I asked about dome end vs. threaded end bypass valve location during cold starts- an issue seen in the SHO article regarding Ford's non-approval of the bypass valve located at the dome end of the filter:


"It is correct to say that front end by-pass valves keep the oil cleaner because the oil does not run down the filter element before it goes into the by-pass valve, but if the filter has a front end by-pass it will be opened longer because the oil in the filter will take more time to warm up and allow oil flow through the filter media."

 

Their response seems a bit hard to understand. I guess the bypass at the threaded end makes the most sense to me as you want the shortest path for the cold oil to have the least resistance to flow. I trust Motorcraft filters and would hope that aftermarket manufacturers making FL1A's for Fords would respect Fords preference/requirement for a threaded end (front end?) bypass.

INLINE SIX POWER! '95 F150 XL
300 Cubic Inches of Low RPM Truck Torque! And twin-I-beams too!
"Drive a stick young man! There'll be time for automatics when you're old and unable."

 

My opinion/interpretation is that a filter with a bypass valve located on the threaded end shouldn't wash particulate off the media and into circulation as a dome end bypass valve may. Of course, difficult to know when the bypass is open or close, so don't know the ideal timing in which to drive of. Purolator tech support had told me that Ford Motor Company "prefers" the bypass valve located on the threaded end. Pure One has their bypass on the dome end, yet their Motorcraft has it on the threaded end. Hastings tech support plus the SHO article makes me feel more comfortable choosing a filter with the bypass on the threaded end.

 

How can we tell where the bypass is located? Where is it on a Mobil 1 filter?

 

If you look into the filter's hole, if you see a coil spring on the near end of the filter cartidge then the bypass is on the threaded end. If you see the coil spring on the far end of the filter cartridge, then you have a dome end bypass valve.
Champion-made filters including Mobil 1, are now switching to a different style of bypass valve that has no coil spring involved. You'll see them as 6 covered holes on the far end of the cartridge metal endcap (if your store has the new inventory). I don't know if this is a good thing or not but Champion claims it's better than the old coil spring style with a higher differential pressure needed before the oil goes into bypass mode.