Originally posted by inspyral
You can have the head deshrouded to match the cylinder bore, but it's not absoluetly necessary. Most people leave their heads alone when they run an 84mm bore, but you should always check your clearances to see if they're still in spec with the 84mm pistons.
very good point, I forgot to mention that. Yea, of course make sure that the pistons, if they're not of stock crown shape, will fit without interference.