Does anyone have any advice on a 2008 6.0L Silverado exhaust and or catalytic converters? I would like to install a performance exhaust, but doesnt the CAT cut the flow more than anything? Is a better exhaust enough?  

My advise is leave it stock as it actually flows well too. But, it is not likely you want to hear this but at least leave CATs in place. They flow well and any real world power gains for changing them is mostly smoke, mirrors and hype. DO expect a loss of lower RPM power and response if you chop exhaust because that engine actually likes a little back pressure to do its best there.  

Thanks Snoman,
Do you have any advice for any power gains for the 6.0L?

thanks  

gcouchoud:
Thanks Snoman,
Do you have any advice for any power gains for the 6.0L?

thanks

Actual one pretty simple one that will yield results you can feel. Run at least 89 octane fuel in it driving and towing (91 or better is best on hot days) and you will gain power and MPG. MY uses a generation 3 knock control system on those engines that lets it tolerate low octane fuel by retarding spark before you here knock. The result of this is reduced power, MPG and response. That engine has greater than 9 to 1 CR and you cannot burn 87 octane without modifying timing curve. I know many strive to buy cheapest gas today but use better gas and it will run better and you will likely find it cheaper to drive too because the few extra percent the fuel costs will be more than offset with a reduction in fuel usage. ( it only takes about a .3 MPG increase to pay out) For what it is worth, I do not run 87 in any of my modern FI engines and have not for years.  

Thanks!!!