Need Advice On Magnum Crate Engine

Because I have been down this road before, I will just say this...
Don't plan on making changes in the future. Like aluminum heads, for example.
You have a short block (blank canvas) sitting in front of you. Do whatever your finances will allow for now. Then it's done and you can spend your time and $$$ on other areas of the car later.
Like new wheels, or an interior makeover, re-chroming the bumpers, etc.
Just a thought.