My advice: pull the engine and have a good machine shop professionally build it for you, that's what i did.
I probably could have done it myself, but i also wanted it balanced, the oil system modified, heck they did everything for me, all i had to do was put the accessories on it , etc, and drop it in. I had invested too much $$ in parts and didn't want to take any chances. and to be honest with you for all i know they may have fly cut the pistons even more- i dunno, i didn't even ask 'em
'cause i was so excited to finally get it!
Oh yeah, my heads ARE WORLD heads too and i also have the same size valves you do..
anyways- goodluck!