It would be fun to drive yes, and would make more hp on a dyno, but you would be quite a bit slower, especially the more you modded your engine.
I had a t56 with my Vortech supercharged LT1, and it was fun to drive, but would have been a lot faster with an auto. My buddy just swapped his t56 out of his turbo ls1 for a th400 with a brake. It's gonna be a very fast car now.