Ok, I am starting my first restoration, and I admit - I am a novice. I have a 69 GTO that has had a bunch of bad work done to it, and I am going to take it back to its roots, starting with the engine (it doesn't have one now).

I know it was supposed to have a 400 in it, but knowing it will never get back to absolute original, should I put in a 400, or should I jsut put in something really neat? What creates the best value (again, knowing it will never go back to absolute original)?

Thanks