There was nothing remotely original looking about my car, but I used stainless pipes with a 4" inside diameter and had a single collector of the same diameter welded onto a plate that bolted ton the headers. Then I used a long, high flow glass pack muffler in each pipe. It was a little on the loud side, make that I used ear plugs if I was driving more than a few blocks, but I gained almost 12 horsepower over the 4 into 1 collectors and the smaller original side pipes that came with the car. Only problem is the stainless heats up quickly and will burn if you touch it. But I had no discoloration except some gold in the elbow of the collector.
Ron
