I kinda remember that and recall it was a huge amount of work? The class rule makers would likely want you to keep the outside of the block looking 'factory' though so there's probably a limit on what you can do to it anyway. No motor plates in the class so the mount ears would have to stay and that's a bunch of weight right there. Most of the weight is in the block itself anyway with thicker main webbing and decks, lifter bosses, 4 bolt mains, etc.