them plug and play bro. make some dimensions up and keep making them longer and shorter and wider, eventually you will find a size that matched the tune (hz) you want to get. and thats your port size. or use a port calc, and plug it into the torres calc and see if they match, cuz thats all any of us will do is put all your info into that calculator. its impossible to just know hoe big your port should be off the top of our head lol pretty much anyone that will comment is using that calculator, if not most, then everyone