You're right, Hank, bigger isn't always better. When I had my old Chevelle, it had an RV cam, Clifford intake and Clifford long tube headers with 2 1/2" collectors. I used a 2 1/2" intermediate pipe connected to Cherry Bomb glasspacks with 2" exit pipes and brought the exhaust pipes out just in front of the left rear wheel. That setup worked really well, wasn't overly noisy, and sounded really sweet, especially when I got on it a little bit. And it wasn't entirely by accident. I had a Holley carburetor book that had formulas in it for designing an exhaust system for maximum efficiency, and I used those formulas to build the exhaust for my Chevelle. I suspect that they're about the same ones that stock 49 posted in the thread above. At any rate, the formulas really do work, and you'll get a lot better results if you use them for figuring out what diameter and length of pipes you need for the exhaust system on your project car or cars.
