Looks like you nailed it- - - -Sometimes the little details make a huge difference! Any variation in the firing impulses at the distributor doubles the timing change at the crankshaft. Since the crankshaft turns 2 degrees for every degree of distributor rotation, it doesn't take much wobble or wear to result in big timing changes between cylinders.
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!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!