[gtmud]

I have had many differant vehicles, ranging from71' F-100 w/400M, to a 00' XJ. My 91 silver. has 156,000 on it, I am running what they call a Syntec blend Castrol 10w40 in both my XJ,and Silverado. Noticed that the oil stays cleaner longer and the milage in both had increased a little. I am also running a K&N oil filter on both. This combination seems to work well. Truck is used as a truck should be, and the XJ, well it too is used for it developed purpose, running beaches at Nags Head, Mudding in southern Virginia. XJ has 87,000.Its your call, but I feel the extra protection is worth a couple dollars more.