Hi Scott,
This is a question that can have several answers depending on which block or engine family we are discussing,and why do you need to remove a large amount?
Alloy blocks have to be treated with some caution when removing large amounts as this can reduce the strength of the retaining lip on the sleeve which sits in a recess at the top of the block bore.Also most alloy blocks have the sleeve installed slightly proud of the deck surface to aid gasket sealing and any set the sleeve may have after installation.
Most of the production cast iron blocks can stand a reasonably large amount(0.050")without any structural problems,However pushrod length and rocker arm geometry will be affected with amounts as large as this along with inlet manifold port match and valley gasket clearances. When you take all these factors into consideration it will probably be more cost effective to look into a longer con rod or a piston with a taller pin height.This way only a minimum of material if any will need to be removed.
Hope this helps.
Regards Jack