I know there's alot of these questions on here, but I wanted to get an answer for this. I have an 87 F150 302 with stock exhaust, except for a glasspack added by previous owner. I want to know whether to get a high flow cat or just gut the two on the truck. What would gutting the cats do to the O2 sensor reading?? The truck has 102,000 miles, so I wonder if the cats have done all they came here to do and need replacing?? Gutting the cats is alot cheaper, too. Planning on a cat back system after I deal with this. No emissions tests here, you just have to have a cat. So, let me know the best route, Sawzall in hand, ready for action.

 

My recommendation is to gut the first cat and put in a high flow aftermarket cat in place of the second one. It'll probably sound better just doing that.

 

hollow out the cat, but put a muffler on that isnt straight through, or you wont move. some backpressure is necessary for a motor to get power. if you dont believe me, try running open headers for a day. you will be deaf, and slow. if you go the other route, put on a hi flow cat, be prepared for a nasty poo smell whenever you are beating on her. with a hi flow cat you can run a straight through muffler, or no muffler and still have the power to move.

 

Interesting poll that I held on my site in referance to cats. Its titled "What to do to a Catalytic Convertor" and if anything its interesting. Check it out at http://www.exhaustsoundclips.com/poll_results.html
its the third one down.