So , i've had many people look at me funny when i tell them that my truck never came with a cat. And while reading thru the service manual, i finally figured out why, vehicles up to 6200lbs GVWR were required to have cats, and my Blazer is rated at 6300lbs. and has the Heavy Duty 350 and is supposed to fall into the Heavy Duty classification for emissions, according to the sticker in the engine bay, So i was wondering what the GVWR is for other years, Did they just up the GVWR to get around emissions or is it really that high? So what's the GVWR on your trucks and what do you think???