Question on ZL1 ebay item 2458413244

[69LM1]

The following quote is in the ad:

ZL1 Block on Ebay
"This is because there are now 4.5" bore sleeves installed in the block. The new owner can choose to run 4.5" sleeves which I believe makes the engine a 477, or change them back to 4.25" to make the engine a 427."

I have been told by no less than three people that you can not put 4.25 sleeves back into this block, at least reliably, and will have heat issues if it is rigged (my paraphrase). Anyway, what is the consensus here? Thanks for the info as I am bidding on this item and want to make sure my ducks are in a row.