STA in the US has the 9.50-16.5 tires in bias ply that will fit the bill perfectly. However, they will run you over $200 a tire, and I, personally, had a bad experience with them as they all severely cracked within 6 months.
https://www.stausaonline.com/tires/sta-super-traxion/
There are also many chinese brand 16.5 trailer tires available off ebay, but they will have more of a car/bus type tread so look a little out of place. Here is a link to some firestone commercial tires that will fit for $205 each delivered in Canada:
https://www.partsengine.ca/189820-vp...SABEgIXEfD_BwE
The part number for the rims for the manacs were actually a bit later than the 5/4 ton, but I believe you can use most 8 bolt rims of that generation in 16", and they will work out. That will likely include Ford 3/4 tons and possibly Dodge.
The brakes and hubs are commercial trailer, so you could change the hubs for possibly 6 bolt, but the 8 bolt is plentiful and cheap....perhaps you are best off going that route.