1983 Delta 88 307ci

So I seem to have an exhaust leak somewhere before the muffler, I think it's where the intermediate pipe flare meets the catalytic converter flange. I remember it looking rusty the last time I was under the car. Over 4 years ago, I had replaced everything from that connection back. The car doesn't really sit for any periods of time to allow water to sit in pipes and rust them out but it just seems like this rusted out too quickly. Anyway, if I end up having to replace that intermediate pipe, I would like to replace the cat itself. I was trying to look up direct fit catalytic converters, I found one made by Walker. Does anyone have any suggestions or experience with replacing a stock converter with one that will bolt right up in place?
Also, on the front end of the old cat, there's a slip connection with an ordinary clamp that goes into a short elbow. THat elbow is then connected to the manifold with a flange and 3 bolts with springs. My question is how difficult will it be to remove these 3 bolts so i can replace it all? the threaded ends of the bolts are smaller than the non-threaded shaft where the spring is, so I have a feeling if they break off it will end up being at that spot and be hell to get out of the manifold. Does anyone have suggestions on getting these bolts out?
Thanks,
Rob

 

Rob, before you remove any bolts holding the exhaust together I suggest you spray them with PB Blaster. This is an anti-sieze compound that eats rust and corrosion allowing you to easily loosen the bolts. Essentially, it is WD 40 on steroids. You should be able to get it reasonably at your local auto parts store.

If you want to replace the catalytic converter I suggest you speak to a local muffler shop. You would pay more having a shop do it but you need to make sure you comply with local laws. Where are you located? I know in OK there are no inspections or smog tests on vehicles. Despite this, I imagine the local exhaust shop I use would still be hesitant to replace a catalytic converter. It needs to be a stock replacment that ensures the car still meets emissions standards. Since my 71 98 didn't have a catalytic converter on it I never had this problem.

 

I'm from New Jersey, to keep the car under regular registration it has to be able to pass emissions testing to the standards of that year, 1983. I've looked up catalytic converters and found a few that are stock replacements and claim to be a direct fit. From the pictures i've seen, they seem to be fairly identical to the old one on the car.

I also checked under the car today and found the exhaust leak is coming from where the intermediate pipe meets the outlet of the catalytic converter. The flare on the pipe is pretty rusted, but the rest of the pipe is in good shape. But I guess i'll have to replace the whole pipe or it won't totally seal against the new converter. Whats the best way to separate exhaust pipes that have been clamped together. It's a flowmaster muffler and in really good condition so I don't want to damage it or shake up the rest of the exhaust trying to get that pipe out of the muffler inlet. Also, assuming I can get it out, is there and expander that I can put into the inlet to get it back to it's original circular shape so it can accept the new pipe?
The only exhaust work I've ever done was on cars that needed everything replaced. Never had to separate old pipes to replace certain sections.