I have an original 1948 B owners manual in front of me as I type and it doesn't give any quart amount on th engine oil. It just says to fill oil until it runs out the top petcock when operating on gasoline and I presume you are. It recomends 30 weight for temps above 32 and 20 for temps below. My brother-in-law, God rest him, told me you shouldn't use anything but non-detergent in these old tractors because as the valve guides wear the oil will end up burning in the cylinders and that detergent oil was rough on them. My does this when you first start it up so I've always used non-detergent. I don't know if it does, in fact, matter at all. That's just what I was told. For the gear box etc. the manual recommends you use 90 weight for all temps above zero. Hope this was some help.