like the title says and are the header interchangeable i searched and couldnt come up with anything

 

ya they arent the same

 

i think the overall height of a b16 header is physically 7 mm shorter then a B18.

 

You may run into some clearance issues if you try to put a b16a header on a b18c. Because the b18c has a higher deck hight so it needs a taller header.

And the only issues with a b18c header on a b16a is that they sometimes hang a little low. So you run more of a risk denting it.

 

thanks for the answers