Frank/Kevin:
The spec's dropped in '96' as Chevrolet moved into a new injection style that has been since proven to not work as well as the eariler CPI motors. Chevrolet also downsized the exhaust on the later models. ADD in OBD-2 and there's the difference.
The spec's listed for the 4.3's are in the S-10 type chassis. The same '94' CPI motors made 200hp/265ft.lbs in the Astro, and full size trucks, and the Bravada, and of course the S-10 SS. This was due to larger/different Y-pipe and a few other smaller changes. I honestly can't see a difference on anything that the bravada had and the difference in power could be just an advertising game to sell the rig over the Blazer.
Small differences yes, but they did make a difference.
Kary