It had something to do with the offset of the wrist pins in the pistons. Those engines ran a very long stroke for torque purposes, and the angularity of the rod at the top of the stroke necessitated a late timing setting to prevent piston slap at idle when the piston was in a "float" position with neither side of the skirt loaded against the cylinder wall. They engineered the wrist pin offset to allow the piston to rock over against one side of the cylinder before the plug fired, and made up the timing difference with a very quick centrifugal advance curve. Making broad-brush statements about ignition timing settings reminds me of Forrest Gump's mama's comments.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
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