[jonnyk]

World Products being Dart blocks. Just be warned that what they say for the block's requisite level of machining is not the real case - they need a fair bit of prep work. Decked and squared, line honing, finish the bores, and indexing the lifters bores are all a good start. You will need to drill and tap for the lifter spider as well, as they don't come ready to run hyrdraulic cams from my understanding. As far as the springs in the heads go, that's an easy swap if you buy the heads from a reputable shop.