stock block at 600+ hp maybe 400 passes total, girdle, aluminum caps don't matter. that's all you going to get, yeah some live longer but..........\ the cracks start appearing then.
so if you get a block that's been raced with 600+ hp for maybe 200 passes and you spend $$$ to rebuild it and upgrade it you still only going to 'safely' get about 200 more passes no matter what