I have a 1981 300 SD, and I changed my oil, and then went to change my oil filter with one that I had bought from an auto parts store using their selection book, but the oil filter is around 2-3"s longer than the oil canister. Thinking it was a fluke, I went to a different place, and purchased a different brand (STP) but it was still the same thing as the one that doesn't fit. I haven't seen this question covered before, and was wondering if anyone could shed some light on the subject?? Thanks