I was wondering if the tranny and transfer case out of a 84 s10 blazer with the 2.8 will work in my 89 s10 blazer with the 4.3?

I was also wondering if all the other 4x4 vacuum stuff is usuable?

AFAIK, the transmission/engine mounting bolt and dowel pattern is different for the V-6. The transfer case is a "maybe" but you'd have to compare the I.D. tags on the cases to be sure.