I have a bad Catalytic converter on my 2001 Blazer. After calling several parts stores most of them giving me the same MF 99009 part number I looked it up and got the dimentions 3" in and 3" out. So I ordered the cat and figured I would order the matching Muffler ordered them off of Ebay because of shipping time and cost. Well whenI open the box's and look at the size of inlet and outlets of both they look larger than the pipes under my Blazer. What kind of issues am I looking at going ahead and installing these components other than having to pay extra for the larger pipes????

Bear

 

If your not doing the install yourself, they should have tubeflaring tools and or couplers in the shop. Iv'e also seen a couple brands of Cat's that are made slightly larger on the flange than stock to facilitate easier fit up over the existing muffler pipe (lap joint opposed to butt) and or larger diameter tubing. Also a set of fresh O2 sensors.

 

You should have gotten 2.5" Blazers did not come stock with 3"

If you are installing it yourself, hit up napa, bring in the exhaust you want, tell them the car you have and that you need step up exhaust couplers. so this will bolt into place on the stock exhaust.

Otherwise, take it to a shop.

 

Just need two 2" to 3" couplers and a welder.
Depending upon the overall size of the muffler, the muffler support bracket that clamps around the muffler may not fit either. But a welder will fix this as well.

 

As I said Most of the parts stores I called recomended the Magnaflow 99009 Cat. I just went off of the info that they gave off of that. I'm deffinately taking it to a shop. I would have tried to tackle it 30 years ago but not now. I'm more worried about getting a low output code from the down stream O2 sensor.

 

Contacted Both of the dealers that I purchased from off of Ebay.Surprisingly they both agreed to let me swap for the correct size. I just have to pay for shipping. Now to my next problem.........

 

If you already have them, just take it to a shop they should be able to make it work just fine, like said above they will have the flaring tools to make it work. I assume you are also having the rest of the exhaust pipe replaced and not just having these welded to the old pipe right?

 

I pulled out my O'Reilly's receipt from 4/30/2013...

I have a 2001 as well...

Magnaflow 99006 cat $87.99 and two 2.5" clamps. $98.97 total with tax.

I used a Harbor Freight tail pipe cutter. Cat slipped right over factory pipes. Installed clamps. I had to put over 200 miles on Blazer to reset ready the computer. Passed ATL emissions test fine. Inspector made a comment about my new shiny CAT with the rest of the dirty factory exhaust. Been nearly 8 months, no leaks, works fine. I do tighten the clamp bolts when I change the oil. They evidently do loosen. No welding at all.

 

Joey Thanks for the info. I had gotten the MF 99009 cat as I said I contacted the guy I bought My cat from and he agreed to do an even swap Minus the cost of shipping. I'm getting the MF99006 cat and I plan on taking it to a shop to have new pipes put on.

 

I did take them to a shop and he refused to install them.

1. Catalytic Converter Diameter size wrong
2. Muffler was Wrong Diameter and set up for duel exhaust and he wouldn't run a tailpipe under the gas tank.