Vise grips or C clamps on the flywheel where it intersects the bell housing. If the bell housing is off already just reinstall the flywheel and screw a couple of bolts into the back of the block for the locking devices to engage.
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!