What's required to run both filters?
Obviously, you'll need two filter canisters. One would need to be the regular style bypass filter with a small-diameter orfice to restrict the oil flow through it, plumbed with the small flex lines we're accustomed to seeing. That filter housing should contain a very fine-media element capable of straining out microscopic particles of dirt. The Frantz-type filter that uses a roll of toilet paper would be a good choice for that one.
The full-flow filter is plumbed with large-diameter lines, 1/2" NPT, I believe, and carries the vast majority of the oil pump output through the filter on its way to the bearings. This one has to be open-weave enough to pass sufficient volume to give the engine the luubrication it needs. For convenience, I'd choose a spin-on filter for this application. Basically, a full flow filter is there to strain out the big chunks that could damage bearings, score the crankshaft, etc. Most of the old Cummins and Detroit engines I used to work on had dual filters, one full-flow and another one a bypass type. Of course, some of them had an oil change interval of 10,000 miles or longer, and on the ones with the Frantz system we just changed filter elements every 10 or 20K miles, topped off the oil level, and never changed the main crankcase oil. It was still testing good on a spectrometric analysis after over 100,000 miles.
Jerry
