Re: What is the best for72'chevelle?
If you're looking for a true dual exhaust with a lifetime warranty, we have our stainless steel American Thunder Systems. The 817200 uses mandrel-bent, 16-guage 3-inch 409 steel tubing while the 817409 has 2.5-inch tubing. Both systems use Super 40 Series mufflers and have an aggressive exhaust note.
Although it has an aggressive exhaust note, the full systems exit out the rear of the car to direct some of the noise away from it. Attached is a pic of the 817200.
As mentioned, the proper choice is going to depend on engine combination and what you're looking for. The 2.5-inch system will be for your stock to mild engine combinations while the 3-inch will support your higher horsepower mills. Hope this helps.