Here's what I THINK to be true: As I said, please correct me if I am wrong...
BECAUSE the /6 was originally designed to be an aluminum block engine, and because aluminum is not as strong as cast iron, the main bearing webs, the top deck of the block, and just about everything else relating to design parameters that affect block strength, ended up being manufactured of cast iron, (when the plans for an aluminum block went away) without changing the specs at all. In other words, this engine should be constructed UNGODLY strong (as cast) because of the foregoing. Add to that, a forged crank (early models,) and a cylinder head that is as robust as the block. It is one rigid s.o.b., at 84 pounds!!!
If anyone has any disagreements with what I've written here, please post the CORRECT info; as I said, I don't know much about these engines....
Thanks for any comments!:read2: