Hi Monster, and welcome to the Tractorforum.
I don’t have a Fordson nor do I know anything first hand about Fordson tractors. The following is a compilation of information I found on the web.
Fordsons Majors manufactured in 1955 and before the serial number can be found in two places, on the firewall in front of the battery, and on top of the flat part of the engine block casting where that starter casting bolts to the block. Explained another way; on top of the flat part of the engine block casting, where that starter casting bolts to the block. The serial number is stamped in vertically.
On tractors manufactured after 1955 the serial number should be located on the block just below injector No. 1. Explained another way; the serial number is at the top of the block just below the seam of the head gasket, passenger side up front on a small milled down section.
Fordson Specifications
Good luck with your old farmer. Go easy on him. Us old guys have to have time to get used to the idea before we are willing to give up our old toys. If you can get your hands on the Fordson and get it going, I’m sure it will be more than adequate take care of your 35x70 farm.