Over the years I have seen several claims that you can swap a car (55/64) third member into a 55/59 truck housing but in all those years I have never seen one thatr someone actually did the swap on. It would require a spider gear swap as the trucks use C clips and the cars have axles that have retainers on the bearings and are bolted in.
Since I have have never actually seen it done I am going to figure that it is one of those pipe dreams that guys come up with an a myth that keeps getting perpetuated because they kind of look like they will fit.
For this one I still go with the 96/04 Tundra rear that if you hunt a bit you can find the desired gear ratio, they should be plentiful in So Africa and they have rear drum brakes. Plus his stock wheels bolt on.
The Yukon gear set is 405.07 from Summit
https://www.summitracing.com/parts/yga-24144/
Going over to Classic parts the bearing kit
https://www.classicparts.com/1955-62...ctinfo/93-514/ is 299.95
The 3.38 ring and pinion is 348.96
https://www.classicparts.com/1955-62...ctinfo/93-513/
That is 648.91 to swap gears in that rear axle not counting wheel bearings, seals and gear lube plus labor.