Well, I went out to my friend/mechanics place to get the cat hollowed AND the resonator removed and when I got there he had just started on his demo derby car for tonight. So needless to say he didn't have time, and there was also a 2002 Chevy truck on the hoist with the rear wheels off so I am still running a stock cat and resonator with 191,xxx miles on them.

Impressive. The resonating sound when the car warm was more is much more agreeable then the cold start burbles.

I suspect (as we discuessed) the proxmity to Joshs car helps resonate the sound giving it a cleaner sound.

Either way

At warm idle, I'm still no louder than stock. That'* for sure. I've maintained my 'sleeper' off the line sound. After I pass them, it'll be a giveaway, though.

Will, my muffler is also a camaro/f-bird muffler...Part #14266 I believe. Should be the 5" x 8" oval.

Yours sounds incredible! Actually just the sound I wanted when I started. Mine sounds just like yours, but not as loud and 'powerful'. Once I get my Hi-flow CAT and get rid of my res I will expect to have the same sound. I can't wait!

May I suggest, if you are going to hollow out your cat, that you just go ahead and put a piece of straight pipe through the middle of it. If you are only leaving it there to pass the "hey look, the cat is there" test, then put a pipe through it. Personally, on my "other" car, I just put flanges on the exhaust and put an "off road" pipe on. When it goes for inspection, I switch the cat back in.

Either way, the reason for the pipe through it, is that, when you hollow out a cat, you are creating some very odd turbulence issues. This may actually hurt your performance.