Meh, sleeve it. We do it all the time. I'll give you $25 for that rejected block. S/F....Ken M
How would sleeving it make the cylinders any thicker.
It may not make it thicker, but that doesn't matter, it absolutely makes it stronger. Even .150(let's say) of virgin 2016 production 100k psi ductile iron is far stronger than .250+ of 1978 crusty grey iron from a Monday shift in Detroit.
We probably sleeve at least a block a month that big power (1000+hp) nitrous and turbo guys smash with "overly optimistic" tunes. S/F....Ken M