I think Mopar Action did one back in the day (It was on 440 blocks but probably still applicable to 400's) and they found the later blocks were cast thicker and more consistent, but were of a slightly softer grade of cast iron. I'd look for a later block and try your luck there
All 440 block, regardless of the year cast, are no where near as good as a decent 400 block for building, trust me on that
You need to remember that not all magazine writers are real hot rod guys with hands on experiences that know something about what there writing about, I've seen that personally time and time again
