Ok...got the formula I needed (thanks Joel.)  So, since the 4th gears in the
air cooled and the diesels seem to be the same, here is what I found:

5.86 Final @ 60 mph with 195/70-14's    4135 rpms
5.43 Final @ 60 mph with 195/70-14's    3830 rpms
4.57 Final @ 60 mph with 195/70-14's    3225 rpms

5.86 Final @ 60 mph with 215/70-14's    3950 rpms
5.43 Final @ 60 mph with 215/70-14's    3660 rpms
4.57 Final @ 60 mph with 215/70-14's    3080 rpms

Note that these numbers are all approximate.  I didn't have the
circumference for the 27 x 8.5 14's (anyone feel like measuring their's?)

What I still need to know:

1.  Does the DZ transmission have a 5.86 or a 5.43 final drive?

2.  Without getting into the whole tire thread, what, if any, negatives will
I experience by going to a bigger tire.  Other than shift of center of
gravity, decreased handling, increase in unsprung weight, greater wear on
suspension and steering, etc etc.

Sorry for the length, but I am trying to prepare everything now so that when
I am more able to work on my van things will go faster and I will lose less
of my summer.  TIA. Scott