A direct quote from the Link:
http://garage.grumpysperformance.com...ain-caps.1014/
"failure to check for cracks or use of a O.E.M. block at power levels its not designed for can and frequently does result in engine failure,
Most O.E.M. SBC blocks are rated at no more than 400hp, we all know guys pushing them to 500hp but much beyond that its a crap shoot and the blocks eventually going to flex and fail".
Now why would "Most" SBC blocks eventually "Flex and Fail"??
400-500 HP is not a known problem on 302's or LT-1's as far as flex correct?