What oil should I put in an early 50's Ford 8N Tractor? It's a 50 - 52 model I believe. A 4 cylinder, of course. It's a gasoline engine. The ONLY thing I could find in the manual about it was how much that it holds (6 quarts)... and that in the winter time to use a 10w-30 oil. So, here in east Tennessee, it gets pretty hot in the summer. I don't think a 10w-30 oil would be all that great for it, but I don't know. I was thinking of going with 10w-40 or 15w-40, or maybe even a 20w-50. I just don't know, but I'm sure someone on here has one or knows what they take. Also, what brand would you recommend? Conventional oils only, of course. Thanks.