I have a Stihl 038 that a customer wants rebuilt, at least a new top end. I looked over the offerings and for the money I can built a 52mm engine cheaper than the original 50mm one. I know this has been discussed before but I'm having trouble finding the thread. I know the holes on the 52mm cylinder will have to be elongated to fit the narrower 50mm engine but is there anything else I need to do? Thanks