I suggest to not use the cast steel crank from anyone unless it is a low pered application. I have not read the rest of this thread yet so may come back and add more here. Factory GM Cast Iron I am much more comforatble with than cast steel from China.
The factory Chevy NUDULAR IRON Crank is very strong and is a favorite of mine for budget strokers. That little recognized crank is good for over 800 hp. It will handle as much or more than your block.
Ed