Here's an extra simple solution:
If your current 350 is in good shape yet, why not just get a set of Vortech heads and bolt those on? Most minimal modifications possible on that route. More power for sure. Better MPG? Probably not. Extra simple? You bet.
You could port and polish them for a little better airflow and a few extra ponies.
Of course, you'll need a different intake for the Vortechs. Maybe add a TPI setup from a 3rd gen? Definitely better throttle response there. Then, of course, you'll need the computer to go with the TPI setup...
That's my vote. Just modify what you've got.