Air raid MIT tube so still has stock lid which prob helps and a catback is just a single side exhaust with a borla muffler so maybe they think it's still a stock exhaust with a muffler and just don't realize it's 3"? lol.

 

So which under drive pulley everyone use or which is best ? I have 12 6.2 ext cab ?

 

i have an u/d pulley and 160 in my 03
can I tell a difference? dunno.....
I did alot of mods at once.
truck runs cooler - trans runs cooler.

 

I take my truck to dealer as Is, no cats, stalled, cammed, slightly built tranny, geared, tuned etc. don't believe that dealer b/s only way they can say something is if the mods caused the damage. N they have to prove it!

 

who makes a good pulley for the 6.2, which company, where to buy ..........

 

is your truck tuned ? if not , tune it this would be the best bang for the buck in your case

 

Ya it's tuned, mods are in first post. Ur sig says bolt-ons with cam... what bolt ons u have and cam? Did u put a converter in with the cam or how does that cam (specs?) drive with a stock converter?

 

I tried the 160 stat in my 08 Sierra and it kept throwing an over heat message and turn my a/c off... i purged the air and burped it and even drilled a 1/8 hole in top of stat to allow air if trapped just like the shop that sold it to me advised and cud never get it to work right... put my factory stat back in and works fine without burping any air out.. but may be the shop that sold it to me sold me wrong one because it was a hair smaller than my stock stat in circumfrance but i dunno.. they swear that 160s work on my 5.3 .... may try a diff brand but never looked for another .. i have underdrive on my Sierra and noticed a small gain .. feels more like it helps to get in the power band quicker.. when i did my mods i have done one at a time so i could tell what it did or didnt do ...

Edit* I've also noticed i am under driving my alternator .. very noticable with me working nights.. at traffic lights and stop and go traffic ive noticed so i am bumping my idle up 100 rpms in my tune and seems to compensate for it without any real noticable increase in the idle without me actually looking at the tach at the rpms ..if ur not in a lot of stop and go driving like me it is not an issue