So, ok, on my 65 mustang I have been using SL rated oil, and a MC oil filter and changing once a year weather or not it needed it. Only drive it in the summer, and mostly long drives, and stored all winter. Last fall when I changed the oil and filter I put on a Fram Ultra. My question is, How many years can I run this filter if I change the oil yearly ? I only drive it about 1000 miles per summer. Can I safely go 3 or 4 years, or should I limit it to 2 years.