Your saying 318 inline just to be sure is that a gas motor? I don't think they were putting the diesels in that early If it were diesel the parts are still available. 6-71's were produced from the 40's thru 80's at least. With 53 series coming in a little later. The reason I was asking was the 6-71 most common was the 238 whereas the 8V-71 base was the 318. They were set to run about 2100rpm but a lot of folks set the govenor 2600 or better, run fine plenty of oil leaks. Spanky proably has better dates on the engines and when they went into COE trucks.