i think GM makes a book that shows you how to soup-up GM v6. i've seen the book and it's got a lot of stuff, pics, drawings, illustrations, and tons of info. it's got stuff for the v6-60, which is the 2.8L and 3.4L, and v6-90, which is the 4.3L. it even gives you the part number of the performance part and the expected horsepower gain. i cant remember the actual book tittle. phone your local dealer for more info.
i went the more compression route, pistons, decking the heaqds, porting +polishing, balancing, cam, etc.
Dont skimp on the bottome end! youll regret it later! the 2.8 is a pain to pull, especially with 4x4!
The early 2.8's have a skinnier crank than the later ones. The later ones can also be stroked with the 3.1 crank. You might want to look for a later 2.8. Some '84 blazers were supposed to have the larger crank, so you might luck out.