What do the numbers in the header models mean?
eg. STRUT PERFROMANCE 4-1 Header
DC Sports Stainless Steel 4-2-1 Header


What is the difference? Do specific engines take specific parts? Are there any downsides from using the 4-1 or the 4-2-1?

Thanks.

 

4-1 means it takes teh four pipes and converges it into one all at once. 4-2-1 (also known as the tri-Y setup) takes the four, puts it down into 2, and then converges the 2 into 1. 4-1 gives you more upper power and 4-2-1 gives you more low-mid range power. general consensus is 4-1 is for racing apps and 4-2-1 is for street...but id go 4-1 no matter what. besides on a stock engine the difference between the two wont be too noticable.