HELP !!! exact size for rebore needed ..quick

[Spanish Dave]

just a real quickie
I am off to the Spanish engine shop in an hour or so and need to know the exact bore diameter for a 289 to take +30 over pistons. I know it is 4.030 inches, but does it need any more clearance to be machined. I have to give the guy the exact measurement in metric units so I need the spot on inch size so I can convert to mm.
anyone on line that can help

 

[slapper]

What I always do is provide the pistons to the machinist so as to bore the block to the EXACT sizes. At times the tolerances of pistons will vary, and this way any discrepancies can be compensated for.