If you are meticulous about breakin and jet it correctly. .004. just be sure it dosent run lean and the shop that bores it gets it round and straight. .045 if your nervous. Remember at .008 its gonna rattle. when you start it.

Two years ago, I put a brand new engine on the Ice with .038" clearance It had been through a dozen heat cycles and its first ride was in practice. Its all about break in/warm up and proper tuning.