If you choose to install a spin-on filter, be sure and put a restrictor bushing somewhere in the return line to the oil pan to keep from losing all your oil pressure. I use a main jet for a Holley carburetor as the restrictor on the ones I install. I prefer the original AC or Fram filter that mounts on the intake manifold. There are usually several of them on Ebay for pretty reasonable prices at any given time. The original canister-type filter has this restriction built into the standpipe leading to the return line already.
Bypass filters do a MUCH better job of cleaning up oil than the full-flow types on modern engines. The filter media can be woven much tighter, since the oil pressure drop across the filter won't starve the bearings for oil. If you can find one of the old Frantz filters that used toilet paper as the filtering media, they claim it will strain out particles as small as 2/10 micron. Full-flow filters catch the big stuff, 5 to 8 microns or so, and let the smaller particles flow through the media. About 30 years ago, I was a dealer for Frantz, mostly selling the filters for 18-wheelers that replaced the LuberFiner 750 cartridges. We changed the filter element every 10,000 miles, added enough fresh oil to replace what was lost during the filter change (usually 1 gallon on a 15-gallon system) and never changed the main engine oil. A sample of the drained oil was sent to a testing lab for analysis. We had rigs with over 100,000 miles on the oil that were still passing spectrometric analysis without a problem.
Jerry
