Even so…the stock crank, rods, rod bolts & pistons all are capable of supporting more h/p than the block can handle. Another thing to keep in mind is that…if your going to be pushing the limits of the stock block there is no guarantee that anything is going to survive. Yes, a main girdle certainly will help everything stay together during a catastrophic failure…but again, there is no guarantee that it's going to prevent damage to the crank or the rest of the rotating assembly.