I use a Baldwin B253 racing filter (same dimentions as Motorcraft FL1A).
The Baldwin filters are super high quality industrial filters. Baldwin really caters to off road equipment, but they also make many high quality auto/truck filters. My Tiger has headers from Sunbeam Specialties (Jet Hot coated), a screw on filter block from L&L machine, and the block adaptor from Dales Restorations. Dale claims that his block adaptor fits ANY header…and he is wrong. I had to put a pretty good sized dent into the #5 cylinder down tube to clear his adaptor. I used -10AN fittings between the adaptor and filter block and I made a custom mount for the filter block to sit where the stock filter was. So I basically duplicated the stock system with SS braided lines, AN fittings, and an easilly removed/installed screw on filter capability. Now when I change oil I drain the pan, screw off the old filter, screw on the new filter, and refil the oil pan.