Go to this link. Several of us had these installed. You'll feel the difference along with hear the difference.
http://www.classicchambered.com/classic/products.html
Bottom of the page: Cobra Packs
Measure what you have and duplicate
You'll need the muffler and the turn out
Dificulty: Welding the SS collector to the carbon steel muffler
I had mine chromed, one had his painted high heat black, one did his powder coated.