My 2004 3.8L V6 Mustang has 4 Catalytic converters.
I have heard that the forward most cats nearest the headers referred to as Pre-Cats.

Apparently (I need to verify this myself), the one on the Driver's side as 2 sensor holes built right into the Cat, while the passenger side only has one.

I am not looking to cut them out. I want replacement high flow "pre"-cats.

What are the correct part numbers for these at www.car-sound.com?
I found a single sensor 2.5" opening for the passenger side (Part No: 91036)
However, I don't see a dual sensor one for the driver's side.

Something tells me that the holes on the driver's side are before/after the pre-cat.

To use the application finder on the site, go with Ford > Mustang > 2001 > 6 cyl., 3.8L

I've tried asking them directly, but they were curt and seemed like they didn't know what I was talking about.

Also, I looked through every thread on the first 10 pages to make sure I wasn't a repeater.

Thank you!

 

Nevermind. I went down there and verified that there were in fact no sensor holes on the passenger side front cat, but one sensor hole on the driver's side forward most cat.

 

Correct. There should be a O2 sensor ahead of each forward-most cat, and I believe there is a sensor in the side of each rearward-most cat on the '04 stock Y-midpipe.

 

Yah, there's one before the small cat in front and one behind the big honkin second one. They're heavier than shat.