Downpipe Size for Twins
Trying to finish up my twin kit....finally...dragging this out into a 2 year project...*sigh*....Anyway, I'm trying to figure up what size of downpipe I need to use.
I have a 408 with twin 67's and my plan is to use dual 3" off the turbos and merge into a 4" before going through the K member. I like the way this setup looks, but it is not doing a step up after the pipes merge.

Hence my question, does it need to step up to a 4" or if I keep it 3", how much of a restriction will it be?
Thx,
Cody B.


