So last week my cat started to rattle and I decided to just pop in a new cat. With little effort I got the cat to unbolt and come apart. (1990 240 DL wagon)

Now it seems the hard part is finding a replacement cat.

I purchased a new cat from IPD with a swivel flage, and after it arrived I realized they sent me one with a flat flare.

But the cat that came off the car has a flare that opens for a seal ring. In fact, I bought a new seal ring thinking that the new cat is the same style.

It seems that IPD catalog only mentions a seal ring for early 80's turbo, whose cats cost nearly 500 bucks.

Looking at the parts, I am beginning to feel that I can mount the flat flare of my new cat to the open flare on the down-pipe with a flat gasket.

What do you think? Is this workable? I talked to some people at performancemotorcars.com, and they think I need to replace the down pipe, because the current flage is superceded by the flat flange. Replacing the downpipe (from exhaust manifold to cat) is expensive and probably a pain in the ass.