It can be done, but not with stock parts, one needs to modify either the upper or lower 620/720 disc brake/ball joint control arms, there are no bolt on front disc brakes unless they are aftermarket or made/fabricated like the way I did it to my 521 work truck.
If you use a 3/4 inch wrench to tighten the bolts holding the upper control arms on then you do not have the weenie bolts holding the upper control arms on I have been talking about, the ones I have been talking about use the 5/8ths inch wrench/socket to tighten them.
I guess I don't know a lot about the 620, I thought when they changed over to ball joints they also used a collapsible column, but DMike says they used a solid column thru 1979, it appears the 620 had a lot of changes made to it over the 7 years it was made, but the column was not one of them.
I can see all your photos, I used the Chrome extension that loads itself so I can see others photos, not the one that the member on here made as I am not smart enough to to manually load his version.
If folks want to see my early photos, they will just have to use the extensions, as I have thousands of Photolame hosted photos published here(Ratsun), and I am not even going to try and fix them.
It's kinda sad what things have come to in this country, Photolame wanting big bucks, Hertz car rentals being cancelled so they can charge 10 times the amount for the same car, and motels/hotels charging a $1000.00 for a room they normally charge $80.00 for just because of the eclipse, they are all price gouging and it appears to be legal.
A Gr 8 5/8 fine thread bolt can take about 180# of torque, while the 7/16 fine thread bolt can take only about 60#.
You need a 5/8ths socket to tighten them bolts, the threaded part really isn't that big, when Nissan went to disc brakes they went to a 3/4 inch head/socket, the threaded part is a lot larger.
I believe he has aftermarket BEEBANI upper control arms, I don't know what size holes the upper control arm mount bolt shaft has, but they likely are small to keep the upper control arms from moving around a lot.
I hate those 5/8ths upper control arm bolts, they were always working loose in my work truck and then breaking, it sucked when they broke as the front of the truck dropped into the pavement.
In the end the threads got stripped out in them holes(driver side), and I had to buy longer bolts that threaded all the way thru the back and stuck out by the shock, I then put big washers on the bolts and then threaded a lock nut on them and tightened them up till I could not tighten them anymore, it collapses that piece of metal on the shock side of the shock tower, never had them break or work loose since, I also used a much harder rated bolt.
I had them 5/8ths bolts break several times(5-6 times?), sometimes only one of them, sometimes both of them, they always broke when I touched the brakes.
I always tell everyone that is switching over to disc brakes on the early trucks to drill them holes out and tap them for the bolts used in the disc brake 620/720 trucks.