You probably refuse to believe this. My fathers company A Duda and Sons ran trucks, big Ford semi's and they used a roll of toilet paper as a filter. One of the big trucks got rear ended while dead heading to pick up another radish trailer. It was hit so hard it ruined all of the rear end. Dad gave it to my brother and me and we stripped it of all the good stuff. When we tore into the engine it was very clean (190,000 miles). Still 55 years later I cant believe it. I have it labeled in a box in my parts room. Putting it on a 292 stovebolt in 2 ton 51 GMC. Doc