What to do with a 400

In my car now it has a slant 6. I want my duster to have a good get up and go and burn out pretty nice. I'm not on a strict budget but I can't afford to build a stroker, maybe down the road I'd like to, I just want to get this engine running good and faster and drop it in my car and enjoyment I don't want to spend my whole life building it and never get to drive it you know just looking for reasonably cheaper

I'm sure you'd find it fast dead stock, cam headers and air gap can get squeeze out a lot of hp.
But right now you can get away with 4bbl and duels.