dunno about keeping the 208..... is he mainly looking for overdrive?
Im contemplating this myself... a nv4500 will keep that low creeper gear and give a final .73:1 overdrive...
Also 1993-1994 chevy trucks had the better of the nv4500's....
I havent looked into this too much myself yet... so i do not know if your bell housing will work..
so what to look at..
bell housing -
~~~ is the bolt pattern the same on a nv4500 & smc?
~~~ my bell housing has extra holes so will the nv4500 bolt to that?
xfer case
~~~ will the np208 bolt to it?
~~~ if not what are the choices ( I think the nv4500 is a 10 spline )
~~~what xfer case adapter is needed?
driveshaft
~~~is the nv4500 longer or shorter?
~~~if so is a new dshaft needed?