Dumb question I know... Anyone?

 

Originally, they were under the passenger side floorpan, roughly between the firewall and the seat. Right where the passenger would put their feet. Also why there isn't much foot room on that side.

However, in your case, that was 30 years ago. There is a chance that some back yard hack removed it and replaced it with a straight pipe, or some other exhaust work to remove or relocate it.

 

 

That's where I tried looking, but there was nothing there. The exhaust pipes go from the engine bay to the muffler and then to the back. I guess it was straight piped or something like you said.

The reason I asked is because there is a terrible rattling sound that's coming from underneath my car when I rev my engine/accelerate. I'm almost 100% sure it is coming from the exhaust system and I thought I'd start by checking to see if the insides of the cat were broken and rattling. But I don't have one...

Anyone have any ideas as to what is making that rattling noise?

 

It's possible that your muffler is damaged inside. Video would help.

 

in my own experience, cats usually only rattled when they were idling, usually in park. your rattling could be due to it being straight piped if it isnt somehow fitted to the exhaust hanger that the cat was supposed to attach to. mine rattles occasionally since i deleted the cat for an electric cut out and didnt attach it to the exhaust hanger

 

Crawl under there (when the car is cold) and start shaking that exhaust. You should be able to hear what is making all your noise.