Boneylander,
If you are looking to increase the midrange it might be easier to raise the top edge of the exhaust port. Given its an 83 I am assuming it has no power valve. Pipe work takes some care and attention to get it to fit right - you also need to be (or know) a decent gas welder. On the other hand, raising the port 1mm (at a time) is easily done with a small round file. Ive done both and porting is less work IMO. Just an idea. Cam.