oh btw external ribs add no important strangth and have nothng to do with the defect in modular blocks. when they split its between cylinders from the main bulkheads/bearings into the lower cylinders.
Spoke with the guy who built the engine again today. He said my engine has the cast crank, and he wasnt sure about the block. He said he would be confident with 650rwhp with the engine the way it is right now due to the crank.