I have used mufflers for a mid-1970's Cadillac on several performance engine builds. ONE muffler has the capacity to handle the exhaust volume of a 500 cubic inch engine, and we used two of them on dual exhaust systems. Those mufflers have 2 1/2" inlet and outlet pipes, and they provide a system with virtually zero back pressure without producing obnoxious noises. Those engines were producing 400+ horsepower, from actual dyno runs I did personally, not some sort of bench racing fantasy pipe dreams. Best of both worlds! It's a lot easier (and less expensive) to make noise than it is to make power.
Jerry
