You can save a lot of money if you can do that type of work. It seems like you are still a young man with two kids and if you are mechanically inclined you could do it and it is fun doing something like that. I used love to work on engines in my younger days, but once I got passed sixty the body tells me to slow down, so I do not do it anymore. But if you are healthy and young, now something about over hauling an engine it is really not that hard. It does take lots of special tools and time, and somebody to give you a hand every once in a while. When you are done it gives you a sense of accomplishment.
You might also consider going to a wrecking yard where sometimes new or close to low mileage vehicles might have the engine that you need and they will pull and start the engine for you for a lot less money then buying a brand new engine. So that way you just transfer some of the parts off the old engine block to the one you will buy. Pull out and put in.
I would try and stay with the same horse power you already have on that 454 engine. Adding more power will just add more stress to the gears on the transmission.
Good luck on what ever you decide and keep us informed as to how your project goes. Might help somebody else with the same situation.