I'll have to go out an measure one, but it is right around 59"-60". I have done one of these conversions for a guy using an SM420 to the 235 bellhousing divorced NP205 transfer case with toyota axles front and rear and six lug "artillery style" wheels, looked very cool just like a NAPCO, should have taken pics. I have heard he rolled it and am trying to track him down to buy the salvage.
Toyota steering box can be used for power steering, I am not sure why that swap is not common for the rear end cause it has the same bolt pattern. The drop out chunk makes it very easy with ratios from 3.23-4.33 (4.10 in almost every 4 cylinder truck) readily available from the factory and toyota gears are cheap from US gear ($150), factory electric lockers are available in later model 4 runners, too.
Chris
