True sleeving all 8 holes is expensive for most blocks but given the value of a 426 block it would be worth doing & it will be better than new . Just don't overpay for the block if you have to do that much repair on it & keep in mind a brand new block is not stupid expensive & is generally cast better with better strength & cylinder wall thickness . I would not run any block @ .060 without a sonic check , minimum is .125 on the thrust side .
IMO a date code block adds zero value to any car as it is still the wrong block & not the one the car was built with , to me a slant 6 car with a Hemi is no more correct than a Hemi car with a date code possible block , there was only one correct engine .