Using the head bolt holes puts a straight-up pull on two 1/2" diameter bolts. If a short piece of 2" angle iron is bolted to the top of the cylinder head with slightly longer bolts than the head bolts that were removed, a VERY secure attachment point for the lift chain is created. I use a piece of 5/16" chain and clevises at the angle iron brackets. Putting sideways shear forces on small-diameter bolts is temptong fate. Dropping an engine as unweildy and heavy as a stovebolt 6 just isn't an option. That's how fingers end up missing!
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!