My father-in-law is the proud new owner of a '57 Willy's pick-up truck. Solid shape, fairly clean without serious rust. Needs a new master cylinder and an air filter. Any air filter as it currently doesn't have one! Engine is said to be original. Actual mileage really can't be determined - 5 digit odometer. Here is what the owner's manual (reprinted) recommends on oil: Above 90F: SAE30 Not lower than 32F: SAE20 or 20W As low as 10F: SAE20W As low as -10F: SAE10W Lower than -10F: SAE10 plus 10% kerosene or SAE5W I wonder if Ford and Honda are going to start requiring 10% kerosene in their new cars in winter? This is obviously a well worn engine so we're thinking a 10W-30 dino oil. Any reason to go with a straight weight oil? He lives in Michigan so summer heat is not an issue. Side note: Also looking for a gasoline lead substitute. Any suggestions?