That much clearance will guarantee a rear main seal leak, no matter what kind of seal is used- - - -the seal can't maintain contact with the crankshaft as it bounces around like a BB in a boxcar.
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!