I was thinking about switching to Mobil Delvac 1 5/40 syn. but was having a hard time finding it locally. When I finally did find some I was put off by the cost. The other day while in Wally World I noticed some Mobile 1 5/40 TDS motor oil at a cost of roughly 5 bucks a quart. After researching it some I found out the 2 are one in the same, according to Mobil. So if your're looking for a good, good priced Synthetic?? Any thoughts. Later Bobcat.