Originally Posted by TIMINATOR

Over 560 EACH muffler and you are using two of them. Depends upon the length of the inlet and outlet pipes and what kind of entry to the inlet pipe what the actual numbers will be. Most all muffs flow better with at least 18"+ pipe on the inlet and exhaust, and yup, most turndowns help the flow and reduce noise also. Allied stainless HP replacement dual 3" in and out only flows about 350/360 total for both sides at once. That's more than the factory stock dual at 280/ 300 for both sides at once (the best one that I have ever seen) and it sounds better than stock on an 8.1, but is a little loud on a 6.0 or smaller engine. Retail price is about $149.95, we don't recommend them. Both of them have dual inlets but route the flow for both sides thru a single hole (Allied) or tube (factory) inside, and that's the big restriction. The factory muff only uses a single outlet, the other is a resonator chamber with very little flow, so the Allied is better there too. I don't understand the concept of replacing something with something else that's only a small gain, and near the same price as the better one. A single unpolished Magnaflow costs more than two Dynomax 17769 or 17770s and flows less too. Stainless is prettier, especially if polished, (more cost too), but I have never had a Dynomax rust out, they, as are most others, are aluminumized before assembly. Install what pleases you, our shop builds performance, and that's what we do here. My posts reflect that. "Bang for the buck" is what we sell. TIMINATOR