Andy:
Have you considered a NAPCO conversion? It is a fairly "bolt-in" process. Also, when you are done, it will have a semblance of "period correctness." While the end result is not as modern as a Blazer conversion, there are many that would certainly value a NAPCO truck of that era. FYI: I changed the differentials from 3.90 to 3.38 on mine using Patrick's conversion kits. With an OD trans and 283 I think it should be OK since I didn't want a rock climber.
