i have been trying to rebuild my 82 trans am, for a couple years now...piece by piece. i was having a brake line issue a while back, if anyone recalls. anyway... i got that done and now i was heading to work today and all the sudden i started hearing muffled sound...almost sounded like the exhaust. i looked at it and the cat came loose but didn't fall off so i tried pushing it back on a clamping it down but it is still making the noise. any ideas? and now i hear a high pitch scream coming from what sounds like underneath the hood but i can't seem to locate it. any ideas? i am effing clueless. any help would be great. thanks
-Worm

 

most likely need to re-expand the pipe to get it back together. Scream? my first guess would be alternator bearing, second guess, AIR pump.