What Moroccomole says is quite correct in regare to infils and the repositioning of psu's. At our place, we reconfig from 290 to 344 annually on 767-300's, and usually align this with 'A' checks or 'C' chechs; nothing is as straight forward as it seems, so don't forget new carpets too. Usually allow at least one whole days downtime for reconfig. It quite often runs to two or three. Hope this is of some help
JFD