I have a new engine being built at the moment. I ordered a new block (its std mag), went and was talking to the mechanic today and head said he wants to line bore the new block as he is not happy with the tolerances? is this normal for new blocks. I know its not a top CB block or similar, but is this a common thing with new block these days?

yeah, I think I can recall someone saying they line-bored new Mexico or Brazil cases cos they weren't straight