http://www.kec.com.au/articles_detail.asp?i=17
"...and the combustion chambers are opened up to decompress the engine to the required 9.5:1 ratio."
"...Clevelands running unleaded fuel like a hemi-style head best, with no quench area at all. They found that even a small quench area led to secondary detonation, which is why the entire quench area is removed on the CNC mill. These are not all-out power heads. They have been designed to maximise port air speed to aid cylinder filling and boost torque using standard 2V valve sizes."
production cranks are pretty much the same, the lack of a test mark doesn't mean it's a lesser crank, it just wasn't tested. i don't believe we've ever run down exactly what the differences between the 4M, 4MA and 4MAB cranks are though, could be the oil drilling angles or who knows what?
"Enlightened statesmen will not always be at the helm" ~ James Madison
