A much simpler way to keep the strain off the thrust bearing flange with the engine in the vehicle is to drive a hardwood wedge between the clutch pressure plate and the back of the bell housing to push the crank forward a little before wailing away on the balancer with your BFH. Being too timid to try to drill and tap the crankshaft snout creates a lot of unnecessary work!
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!