Originally Posted by RPM WS6

Just keep in mind that yours won't have the same lope/chop going though cats and a stock muffler. In addition to being muted (volume) it also won't be as sharp/defined...for lack of a better term. So if you are looking to match the idle quality (other than volume) of any given cam based on a sound clip that involves aftermarket muffler(s) and a catless system, you might be disappointed in the results of said cam in your application. In other words, using cats and a stock muffler isn't exactly the same as just turning down the volume while keeping all the other qualities the same, it also "smooths" the exhaust note and makes the idle seem more mild (less chop/lope).

For example, one of the configurations on my Trans Am many years ago involved installing/removing cats with an otherwise unchanged exhaust system, this was after it already had an aftermarket cam and louder than stock muffler. The change (reduction) in lope/chop at idle was pretty noticeable after the cats were added, even though it already had a louder muffler.

Originally Posted by SSquicksilver

What you just said is so very true, I have seen a few clips on youtube of the said cam, and no two are alike or even remotely close IMO. The clip on the white Vette definitely has the best lope of the bunch! There is a blue GTO (extremely clean BTW) with the same cam and it does not have anything near the lope of the Vette as the vette idles a bit faster. The kicker is they both have a very loud exhaust.....perhaps the exhaust is bit quieter on the GTO to go with a lower idle but I have no clue if the cars have cats or not.
Thanks for the good info RPM, you are right on the money Sir!