Depends on the budget and the intent...on my QB, I left it as original internally and externally as I could; stock crank, rods(?), lightened Ross pistons, newer grind solid cam, 583s, stock intake, carbs etc. You could probably put it in a numbers car if needed.
But on the side, I am building a bigger one using a 656 block, BWR heads, etc. I just felt like preserving as much of the QB combo as I could for now.