I called Winters, and they recommended using a good brand name 70-90 grade of non synthetic for the first night or 2 of racing, then use Mobil One synthetic, 70-90 and not get carried away with how much you put in, I was told to level the car as much as possible, and by eyeball, fill it to the lowest part of the axle diameter, which in a midget, is about a quart, you might want to double ck with them, to see what your individual needs would be. Bob