Reply to "Unpleasant surprise :-("

When sleeving a block, the block is bored slightly smaller than the sleeve. Then the sleeve is frozen to shrink it and/or the block is warmed up to make it grow, so when the two parts are joined and temperature-equalized, the sleeve is held very tightly within the block by this 'interference' fit. Running the engine warms everything up, but the two different dimensions still holds the iron sleeve tightly in the iron block. Naturally, this stresses the block a bit. All I'm saying is, due to very likely falling thru the side of the as-cast cylinder, one can use use minimum interference fit dimensions to minimize that off-center stress. The machine shop will be familiar with the concept- and you may get lucky and NOT fall thru one side of your bad cylinder.

In one respect you're already lucky: I once bought a locked-up engine like yours cheap. On teardown, I found the loose wristpin had worn clear through the cylinder wall and wrecked the main bearing supports. I salvaged a few fittings, bolts and the heads and scrapped the rest. Life is a learning process....