Clamp a pair of vise grips on the flywheel ring gear and let it stop against the block. If the flywheel is already off, screw a couple of bolts into the flywheel mounting holes and use a pry bar to stop the crank from turning. The simplest way is to use an impact wrench on the puller after lubricating the puller jackscrew liberally with anti-sieze compound. You can also use a big crescent wrench on one of the legs of the puller. If the oil pan is off, wedge a piece of 2 x 4 between a crankshaft counterweight and the oil pan rail.

"This ain't rocket surgery!" You gotta be smarter than a dumb chunk of cast iron!
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!