Hypothetical 360 magnum build

Well I don't / won't race it, probably don't need more than 3500 rpm anyway/ but I want to make "idle to 4500" better and if I can do so with what I have collecting dust, all the better.
If I can't, or if there's some reason it absolutely won't work out, !parts are gonna "crash" or blow out the side of the block, etc. I get that. I also had the joy of building an engine years ago that was "lots of noise but less power than stock. Don't want that either. I'm not saying I don't want to or can't spend "any" money on it but what's wrong with using what I have if I can? I don't think I would be able to get pennies on the dollar of money already spent, trying to make lemonade out of lemons. But I want it to be an improvement over stock, at the same time
I'm looking at having to buy a set of heads most likely at any rate, and with all the talk of aluminum heads I'm considering that. But I want to work with what I have at the moment and that's short block parts.