Have a set 1 5/8 2 1/2 collectors tri y DT WITH 2 1/2 y pipe and 3" collector after y that hooks up to factory exhaust . On for 6 months . Perfect fit on my 2010 sierra but fits 99-13 gm. Real impressed with fit/ gains were awesome . Paid 650 , will sell for $400 obo shipped

 

What's the part number for headers and pipes? Does it have cats?

 

Doug Thorley Headers

Part #: THY-310Y-1-C

 

Why are you removing and selling? Did you run them with your stock cat back? Any vids?

 

I bought them before I added a supercharger, so I'm changing my exhaust. Ran with stock cat back with magnaflow weld in muffler. Had tons of compliments . Ran the supplied ypipe in kit that has no cats.

 

What did you think about performance gain with these? Was the low end affected?

 

I don't have any times but I have raced bros truck which is identical to mine and we were dead heat for last 3 years . After headers and airraid MIT pipe it was huge... He says I'm like 2 truck lengths ahead. My gas milage went up to 1.5mpg also!

 

Will the headers hook into the stock exhaust, before the cats, with no modifications other than cut off the head pipes and weld in the headers?

 

Pm sent. I will take them.

 

I forgot to update, sold