I just couldn't see swapping over the entire driveline from a Yota. That little 1.3 in the Zuk had a cam and rebuilt engine and it would haul with Zuks that had the 1.6 conversion on smaller tires.
I have some extra '85 axles that I planned on putting in, but decided against it as I never had any problems with breaking birfs or shafts.
I wheel hard but I know the limits of axle parts and what the truck should and should not be able to do. I have been really lucky not to break much over the years but there will always be unforseen issues that you cannot control.