I've got an 87 F150 with the 5.0L EFI. The front cat is rattling like it's broken up internally. It's not the heat shield because I took it off, and it still rattles the same. I want to gut it, and I'm wondering what is the best way to do it. I'd like to do all the cutting myself, and get a shop to weld the pipes back together (I have someone who will do this, they just won't cut it out). Can I cut the pipe at the exit of the first cat, and hollow it out with it still in the truck? I want to minimize the amount of welding that has to be done. I don't want to replace the cat either, because I have an engine swap in mind for the future, and I'm gonna run a complete new exhaust true dual with dual converters, and I don't want to have to buy 3 cats when I can get 2 with the exhaust. I want to leave the second cat, but one muffler shop I went to said that if the first cat is bad, the second one is too - anyone know if there is truth to this? I want to leave the second cat for now, but if it's bad too, I'll consider getting a cheap cat that will last me till the new engine. I have emissions testing here, but I know people, and they say that's not a problem (it's not what you know, it's who you know). Sorry to be so long with the post, but I have a lot of questions. Thanks for any help you may be able to provide.

 

I would leave those cats in since you have emittions testing in your state, unless you are VERY confident someone will squeeze you by. I hear they really stick it to you if you get caught without cats. I personally am running a true dual setup without any cats from the manifolds back. We don't have any emitions testing in ND so I can easily get away with it. But if you still decide to gut them out I probably wouldn't be the right person to say. I bought my truck with the exhaust on it. All I can say is that it isn't a professional job by any means so im guessing a home job or one worthless welder. Keeps creaking and has exhaust leaks round the glasspacks. You will like the sound.