Took it to a nearby exhaust shop, they said the cats are bad enough to where it'll hold the truck back and get bad mpg but not to limit it to a certain speed. The blown head gaskets definitely didn't help them either. Any suggestions on what the best replacement cats are for these trucks? I've heard from one source that the front cats are just pre cats and I could replace both on one side with a single magnaflow or equivalent but I was told by the mechanic that they are all cats and none can be eliminated.

 

CA requires CARB certified cats I think. Expensive. The shop should know what has to be bought.

 

The shop showed me the magnaflow option for the CARB certified cats. In total around 900-1000 for each side. Now comes the part where I decide if I should spend the money on cats or just sell the thing (if it can pass smog)

 

It should pass smog if there's no CEL or stored codes.

You could always sell it or register it in another state that doesn't have emissions inspections.

 

That's what the guy at the shop told me too. I might try to register it in another state and swap em out with universal magnaflows. I won't delete the cats completely as I've heard that destroys the low end power. Or I'll just sell it and get something 75 and older so I won't have to worry about emissions again

 

In NC, 22 counties require emissions tests. A couple years ago, the state exempted vehicles that are 20 yrs old. CA probably would never do that.

 

After reading through forums for hours about the exhaust systems on these trucks, I thought I'd ask to make completely sure before I make a possibly grave mistake. I'm told that the magnaflow cats are the best replacements for these trucks, and owners commonly cut out the pre-cats and use only the magnaflow cats instead. Would it be possible for me to replace the rears with magnaflows and hollow the pre-cats? To my knowledge this should still pass smog and not throw a check engine light but I want to ask those who know way more about these trucks than I do.

 

I'm in a non-emission inspection area - one of my precats just rotted out. The local muffler shop cut them out and replaced them with pipe. No CEL. Here, that's legal. He told me that if the main cats go he can replace them with universals for around $200 each. The main (rear) cats on mine have the rear O2 sensor bung in the center of the cat, not behind it, and he has universals with center bungs.

Legally, I think you can gut your precats and replace the main cats with center bung CARB approved universal cats. You won't trip a CEL and that "should" pass a visual inspection. Discuss this with a muffler shop, they know what's legal and what's not. I know for a fact you can't cut out the precats in CA.

 

I'll discuss with a muffler shop to triple check. If I can legally gut the precats and replace the main cats with universal replacements, that'll be exactly what I want. Im not too worried with the visual as they'll still look complete on the outside, it's the "sniffer" test I'm worried about passing. I still need to crawl under the truck and see if I have the sensor in the center of the cat or behind.