Well, what's your budget??? Turbo's aren't cheap, but horsepower seldom is. Converting it to a 347 stroker is another option. Add a good set of aluminum heads, and matching carb and intake with a matching camshaft and they make good horsepower.

Might be best to decide what the primary use is going to be, how much money you're willing to spend, is fuel mileage a consideration, and how street friendly you want the engine to be. Once you have a plan in place, picking the correct parts is much easier and a lot more accurate!!!!!