Modifying the exhaust on 80's Spider

[Spiros Angelopoulos <spiros@domain.elided>]

I have an '85 Spider with the standard exhaust where the catalytic 
converter is welded to the pipe that connects the exhaust headers to the 
muffler.  The car has developed a very loud noise emanating from the 
slightly loose heat shield close to the headers.
  I was told a while back that it is possible to replace the one-piece 
catalytic converter/exhaust pipe with those from an older 70's Alfa that 
would have the bolt-on type cat.  In this case I would be replacing the 
whole assembly with three pieces, one from the headers to the cat, the cat 
itself, and one from the cat to the muffler.  Does anyone know which Alfa 
model would be a good fit?

Thanks in advance

Spiros
'94 164LS
'85 Spider

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