You can make your 305 peform well. It's really not any different than modifying a 350. It's just another small block, so all the basic principles apply. bore it out a little, get a good stout cam, flat top pistons, 4 barrel, or fuel injection. I had an '85 IROC that was a 305 TPI. That was a fast car, I dig those TPI units, they look good and sound good.

The only problem is, unfortunately, that a 350 with similar build is still going to outperform you. But you can definitely eat a few.