Got a 1968 M72 Jeep (Military) Truck. Has A 231 Overhead Cam 6 Cylinder Tornado engine. Most folks never saw or heard of this engine for good reasons. It is a low powered, poorly designed Lemon that the US Gov bought. It has 2 major faults, along with a 1000 minor ones. Fault 1, the cam lobes and valve wear out quickly due to poor luberciation. 2. The distributor shaft that drives the oil pump has a fiber gear on it that can fail and as far as I have read there are no replacement fiber gears available. The FIX I have a new cam and valve lifters. So Am I on the Right Track: The Army / Kizer co says use Gov 30 wt non detergent oil. That results in the quick Cam Wear. (This engine has 35,000 miles on it and 4 cam lobes are worn flat/ Zero compression on those 2 cylinders). I plan on using 00-20 wt Penz Full Synthetic in it. The much thinner oil plus the much greater Lube of synthetic should allow more oil to get to the Cam and reduce the wear. 2nd advantage the thinner oil should be much easier on the fiber gear that drives the oil pump. NOTE: I have ran synthetic in several old Old engines, 235 chevt 6, 300 ford 6, chevy 283 ....... No issues noted. Sooo Wish me luck or tell me some good reasons not to proceed. Your thoughts please. 1 addition, The rings seem to be fine, it quit smoking after I replaced the valve seals.