Not that thick? Dangerously close?! 2.3 with .030 overbore? Where on earth did you come up with that? You can have the block set to a 2.5 and even in some rare cases I have heard them getting near 2.8 for the offroad races...

I would not worry about the .030 overbore, the guys at the shop will let you know before hand anyways.

Also if your only doing a stock rebuild then its best to get the overbore a little as possible anyways.