I copied over some links from a different but related discussion about chambered exhaust.
Reference to the original discussion: http://www.camaros.org/forum/index.php?topic=9380.0
Below are two links to two YouTube sound bites of exhaust systems on the 1969 Z28s for reference and help in choosing an exhaust system for your '69 Camaro. This first link is from CRG member jmcbeth's completely stock '69 Z28 (…and very nicely restored Z28 I should add…) with the Gardner's transverse muffler system including the resonators.
Jmcbeth’s YouTube Link: http://youtu.be/8PMF8311ACA
This is the sound bite of my "relatively" stock '69 Z28 302 but recently upgraded during the motor rebuild with Comp Cam's solid roller cam kit 12-770-8, springs, lifters, push rods, cam button, and #1804-16, 1.5 ratio Ultra Pro Magnum Roller Rocker Arms. Initial timing set at 12 deg. BTDC, idle speed set between 900 - 950 RPM. Results: Very responsive and reliable power from 2200 to 6200 RPM. The sound bite is through the stock exhaust manifolds and exhaust system with the transverse muffler, without resonators. This solid lifter cam was selected to be relatively close in sound characteristics to the stock 30-30 cam, yet more usable power lower in the RPM range. You will notice it has a bit more crackle in the sound note.
My YouTube Link: http://youtu.be/bSGjLtTmmls
If some else has Gardner Exhaust’s chambered system on a stock '69 Z28, please post a similar sound bite. This will provide an interesting side-by-side comparison with jmcbeth's stock transverse muffler system with resonators.
Thanks and enjoy the music!