Trying to figure out the difference in a 4-2-1 and a 4-1 header for my D16Y8 and which one I should use thanks.

 

I used the DC 4-1 ceramic header on my d16y8. I liked the look over the stock and there was a nice power gain over the mid-high rpm range. It also made a nice sound when vtec kicked in. The only bad part about the aftermarket header is it really makes the engine bay hot which is bad for a short ram intake like how i have.

 

4-1 is slightly more hp in the upper rpms but a 4-2-1 will give you more low-end torque and hp. i would get the 4-2-1 it will help move you off the line. dont choose one on the basis of looks.