You should be able to make the crank drop 1/8" or so by prying on opposite sides of the flywheel ring gear, which is plenty to replace the rope seal. I usually back the main bearing bolts off about 2 turns- - - -can't imagine why it would be necessary to drop the other main caps 1/2"!
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!