I think you are going to have to be more clear on what you are asking. THe ports on the stock cylindar are huge, by stock moped sizes. Most 70cc kits do not require case matching because the case is already big enough. If you want to do some porting on the the stock cylindar, then it would not hurt to match the exhaust port to the expansion pipe you are using and widen a bit. I do not think there is a lot of point to expand the transfers in the case unless you are putting on a big scooter kit.