Here is a copy of the rules for folks that want to look. It's a farm stock pull with any age of tractor allowed. They don't really have a class for a div.5 Farmall. They used to run a hobby stock class and there it would've needed a saftey blanket and ETC.
I think there should be a phone number for you to call. I've ran smaller front tires there in farm stock and there are one or two regulars that don't have stock fuel tanks too. I have never seen them tech a tractor.