How far can a 350 Chevy engine be bored out?

A 350 Chevy small-block can generally be bored out to a maximum of around 0.060" overbore. Going beyond that significantly weakens the cylinder walls and risks cracking, making it unsafe and impractical. Some machine shops might push it slightly further, but 0.060" is a commonly accepted limit for maintaining reasonable strength and longevity. Even at 0.060", it's crucial to have the block checked for cracks before and after boring.