I just put a full TTI h-pipe system and headers on my 360 (smog motor w/edelbrock carb) and it sounds very tame. Tried the super turbos, then switched to Ultra-flows for more bark. It still sounds very mellow. The exhaust note is pleasant, and excellent under full-power acceleration but very tame at idle and low-rpm. Exhausts are such a weird thing, my 273/2bbl with a cheap summit 2.5" system with turbo-style mufflers sounded incredible, about the meanest bark you can ask for. I have heard that blocking the exhaust crossover in the manifold will change the exhaust note. I'm getting ready to plug the crossover on my Eddy RPM (fuel boiling problems on hot days) and curious if you all have noticed a difference in sound when you changed to a manifold with no crossover such as the M1, air-gap, etc.