Doug thorley tri-y's
#15
Only pic I really have, will try to get better pics later

Here is what they sound like through a cut-out:
GMC Sierra MP112 - YouTube

Here is what they sound like through a cut-out:
GMC Sierra MP112 - YouTube
#16
It wont be for probably another month or two but when I do buy the Tri-y's and get them installed I will get some pics up of the whole process. I am looking into getting a dyno run done before and after the headers but I don't know how much of the HP increase will be from just the headers because I am going to get my 8.1marine injectors installed during the same time and will get the re-tune for them both at once.
#18
Steve Bryant has these headers installed on his Yukon 2500XL 6.0L. Here is a link to his photos of the headers. Webshots Rides offers thousands of the best car wallpapers.


