If you call 310.71 a 310, then you'd have to call the standard bore (4.00") at 301.59 a 301. Since we're rounding up to 302, most would agree you'd have to round up to 311.
this is just the first site that i found the other night when i was tryin to figure out what my 351 would be bored over.. i think i came up with a 312?
Rusty said "when i was tryin to figure out what my 351 would be bored over.. " -- that's why I calculated for 351, guess you typo'd. I just plugged into it for .030 over on a 302 (4.03 X 3) and it gave me 306. I input .060" over (4.06 X 3) and it gave me 311. You must've input something incorrectly - try it again.
We're hereby starting a movement to call all the 310's -- 311's. We also need to start calling the 331's -- 332's. Yes, that one's off too. If we don't, then we have to start calling the stock motors 301's. And that'll really screw things up. Of course, when you tell the old timers that you've got a 332, they'll think it's an old FE block, not 5.0L-based, but what the heck.