o-ring is a -114 a very common o-ring. I use Buna-n are you could step up to Viton your call... Use round o-rings for this application not square cut o-rings.
You throw out the o-ring engineering specs for this application its not a normal o-ring sealing application the valve needs to move freely with just enoufh drag to keep it in place.
You can use a .25 cent o-ring are a CNH $5.00 o-ring its your call they all come from China with an original cost of 10 cents...
Yes I did buy a CNH $5 o-ring to satisfy my curiosity from that point on I I brought a bag of'em are used what I had in my o-ring kit...
A kit like this has saved my bacon a many a time. Are Google
Buna-N O-Ring Kit, 70A Durometerhttps://www.amazon.com/dp/B005LRSAT0
To satisfy your Ford o-ring addiction you will need these o-rings to fulfill your needs.https://forums.yesterdaystractors.com/viewtopic.php?t=1342583&highlight=oring
Other than my kit I keep these o-rings on hand...
I will list others late