Yes the INSIDE diameter of the glasspack inlet would need to be 2" but that's not the only thing to consider. Unless the inside bore of the entire glasspack is at least 2", you could have unwanted backpressure. If you could hold the glasspack in your hand before you bought it and then drop a 2" ball through it, you'd have what you need. A golf ball is I think 1 3/8" for example. Pep Boys always has glasspacks, though I'm not sure of the bore. Expect to pay more for a true 2" bore. Most are 1.25" to 1.75". Good luck.