Mine 351C-2V is bored out to .060" - no worries. I've let the engine run during cam break-in, ran it idling and all sorts of other tests to bring the temps up, and it hasn't seen anything over 200 yet (laser thermometer shooting in just about every place imaginable on the block, heads, water pump, intake, temp sensor, etc.). No forcing out of coolant, although I do have a burp bottle.
I also went with everything new - I'm sure the roller-everything options I went with have helped reduce friction (and friction-generated heat) greatly. The monster 7-blade fan probably hasn't hurt, either. The ceramic-coated headers is what gets me - I haven't seen any temps higher than 300 on the headers themselves - probably has something to do with the ceramic-coating, I'm sure. Things I've read about headers says this is not normal... but again, just idling vs. actual driving.
However, I have not yet had the car on the road (under load) with the engine compartment 100% sealed up (hood closed during normal driving conditions) - so I'm sure there will be a difference in temps when it's finally on the road.
If/when the engine's time comes due, I'll sleeve it then [if possible] as I trust my machine shop (so far, so good). If the engine grenades, I'll come up with another 351C block, and most likely will go with the exact same 2V set-up I have now - might go with Edelbrock heads though.
My opinion: I'm not entirely done formulating my opinion on .060" bores with my set-up, but I hafta say, "so far, so good." It seems like the overwhelmingly popular opinion is that Clevelands have are too thin-walled to survive anything over .040" - to which I say, "It depends on what you are going to use the engine for." If .060" was such a bad thing for the Cleveland's survival, then why do they have such a large selection of .060" parts for the Clevelands? I didn't have to "special order" my pistons or rings, after all - got 'em straight "off the shelf" from Summit Racing (no back-order... shipped the same day).
My theory is that the people with those opinions are wanting to race their Clevelands, so yeah - .060" might only be for short-term survivability in racing conditions... and makes perfect sense. But, just putt-putting down the road going to work or an occasional weekend outing - I'm willing to roll the dice. Worst case scenario: my 44-year-old engine that was seized up when I bought the car finally grenades - oh well. I'm not a racer... the car probably will never see over 100mph (well... maybe once or twice)... and I currently only roll about 6-7,000 miles/yr on my current daily driver. I like my odds.