Exhaust Question on 1985 K10

[InVision]

A friend mentioned to me that the original Catalytic Converter may be bad on my truck. He suggested I should just have then local muffler shop weld a bypass pipe on instead of replacing it. I know the previous owner removed and bypass the emissions on the 305ci engine when they put a new long block in it. Not sure it is functional anyway.

Hoping forum members can give me some guidance.

Thank you...

 

[CSFJ]

Depends if the muffler shop in question will do it. The fines from the government are big enough now, that even some if the shadier places are getting gunshy about removing the converter. In all reality, if the rest of your emissions equipment has already been bypassed, then there's not much reason to keep the cat. You may notice the exhaust will smell different, may even see a slight bump in mileage. I'm guessing you're in an area that doesn't require vehicle inspections?

 

[InVision]

No inspections that I know of here in NW Florida. Probably would cut out converter then put bypass pipe in and take to shop to have welded in.

M

 

[CSFJ]

Fwiw, a lot of exhaust places up here won't even work on it if the cat's been removed. Even if you took it off, they'd still be liable if they're caught. Might want to phone ahead and see if there's a way they'll work around the system.

 

[InVision]

Thanks

 

[InVision]

Not really fond of loud trucks. Will the CC make it a bunch louder?

M

 

[1987 GMC Jimmy]

No, that really lies in what muffler you have. It may have a marginal affect, but I've done it and couldn't hear much difference if any. In Mississippi, places will delete the cat no problem, but I asked a place in New Orleans the other day to get rid of the punched cat altogether on my Caprice, and they wouldn't do it.

 

[smoothandlow84]

Depending on your local laws......you may need to remove the cat (s) and then the muffler shops will add a delete pipe section, then add the muffler(s) of your choice. Here in Az for example, any vehicle older than 15 years can be registered as a "historic" vehicle which requires proof of collector car insurance. Once insured, the department of motor vehicles will no loger require ANY emissions. I was able to remove all of the emissions equip including the cats and installed long tube headers and dual flowmaster mufflers. It make quite a difference in throttle response and a bit more mileage.

I removed the cats first before adding new mufflers. There is a slight noise difference without the cats under acceleration. The noise from the mufflers will depend on where under the truck they ate positioned. My mufflers are under the bed and there is barely any resonance in the cab even under acceleration and I have dual Flowmaster 44 series which are commonly louder than the 55 series.

To register my square for 5 years is $56....and NO EMISSIONS...EVER.

Florida more than likely has the same requirements since there are a lot of collector vehicles there as well.