Cam will change the sound and idle quality. Generally, the bigger the cam the more lumpy it idles and sounds. Firing order has some to do with the sound as well as the actualy Cubic Inches of the engine. Headers, heads, etc. will also vary the sound of the engine somewhat.
Mufflers probably determind sound the most. Glasspacks are louder than turbos. The stock sbc with headers and glasspacks would sound loud. Kind of hard to describe the sound though. I personally dont think they sound that great but its all relative I suppose.
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