To turn or not

I bought a motor from a guy I drove 50 miles one way and when I got there he said it was behind his barn. I freaked out and there was probably 20 motors in the dirt covered with a tarp, he said they are all good I filled them up with oil, used drain oil. He had a lot of equipment and every time he drained the oil out of them he put it in the engines he had. It was filled to the top of the valve cover and he wanted the oil so he popped it out of the ground with the back hoe and drained the oil, pulled the valve cover and it looked good no rust except for the bottom of the pan. I changed the pan checked it out and all was good.