The 84 svo had 175 hp and theres lots of mods you could do to pick it up. Just search around in the 2.3 section, maybe take a look in the tech section sticky, theres lots of things in there. It would probably be a good battle with a stock auto 5.0 if you were 5spd but with a few minor mods it would blow it away.
yes you can use the tbird cpu. you should chek out gt350's site it has a walk through of the whole procedure. it is no big deal. it is easire with a svo cpu. The 84 cpus are easy to come by though. I think I have one or 2 laying arround the hard part is the wiring harness. most 84 harensses are shot. so you have to pick the lesser of the 2 evils.