Just to give you an idea of how overrated production ford 4 bolt blocks are, we use to turn 8500rpm every weekend on a production 2 bolt 351 cleveland. The girdle is great for holding the split block together. The killer regardless of 2 bolt and 4 bolt is crank walking. Thats what starts the whole scenario. Look at some production ford 4 bolt blocks. The outer bolts do little. Theres a reason all good aftermarket blocks use a splayed cap