VACLee is the top dog on VA series here, I know about enough to make a small pimple on his backside but here is some study material so you can understand better the info he has provided and pick his brain some more. I had owned a 1953 VAC-13 for many years and worked on several others but didn't have much to do with the pre 1949 models.
The 1st link is the pre 1949 VA series tractors operators manual that is showing the pre 1949 type pto and hydraulic lift with the high pressure belt pulley driven pump. This is a good manual with lots of info, worth the time to read it all the way through. The hitch & PTO changed in the 1949 model year as well as other items in the VA series tractors.
The 2nd link is a later VA series tractors parts manual. It has a break down of the older hydraulic lift & high pressure pump and the new Eagle hitch lift & low pressure engine gear driven pump. I only see the later PTO but I just scanned quickly. Some pages will have serial nrs at the top that indicates to what years that parts page pertains.