2.7 mods?

I went back and looked under my pickup again. The stock manifold drops to a Y-pipe, which is integral to the section holding both catalytic converters. There is no flange between the Y-pipe and the front cat, like I thought. That's why the headers won't bolt up to a dual cat system.

By the way, Rider, I think you are misunderstanding what "cat-back" means. It is simply an abbreviation of "catalytic convert-back", meaning the system bolts to the flange aft of the rear catatlytic converter and goes all the way to the exhaust tip, including the muffler. The systems come in three pieces: the front section bolts to the flange aft of the rear converter and extends to the muffler; the muffler, which you can either clamp on or weld on; then the tail pipe section, which clamps to the rear of the muffler and routs over the rear axle and out the rear or side behind the rear wheel.

I am happy with the fit and finish of the Magnaflow system, although it is a little louder than I would like. Has a nice tone, though. It is advertised as a high-flow muffler. From what I have read, mufflers like the Magnaflow and the Flowmaster have no fiberglass sound dampening material inside. They are designed with baffles inside, such that the sound waves at certain frequencies (where the vehicle is loudest) reverberate inside the muffler and cancel each other out. It is the same concept used in noise-cancelling head phones (except the headphones do it electronically). Since it is passive noise cancelling and not active (like the head phones) the mufflers are designed to perform (muffle) best at specific frequencies that are produced in the muffler at specific rpms of the engine, so at other rpm levels the cancelling isn't as good. That means you have a high-flow muffler without restrictive fiberglass inside that can collect moisture and rot the muffler, but that you sacrifice a little sound dampening at certain speeds. They can sort of tune the muffler for the sound they like by adjusting the design.

I like the fact that the Magnaflow system is stainless steel. Here in Pittsburgh, where they salt the roads in the winter, that's a big plus for durability. Like I said, though, it is a bit louder than I would like, but not objectionable to me. At highway speeds it seems to be quiet enough that I can enjoy my CDs (and I don't play them loud).