Guys, it's time to apply Occam's razor here- - - - -we're not dealing with a museum piece like a Duesenberg or something similar. If the block can't be made serviceable with a Heli-Coil and some low temperature bronze welding rod, scrap it and find another one!
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!