OK, so I bought a replacement cat for my '89 and went with the MagnaFlow replacement center section...the one that replaces everything between the manifold and the Y-pipe. Anyway, I unpack it tonight and the flange on the air tube is nowhere near square. The weld is good, but I don't know if it's supposed to be at this angle (my car is 30mi from here in the shop I share).

See attached pics - does this look right?

 

should be fine. just make it fit.

 

just took one off tonight IIRC the air tube is mounted into a rubber hose so there should be some twistability (ooo new word) to make things line up

 

http://dictionary.reference.com/browse/twistability

 

If you still have the factory air tube on the car, the end is metal and not rubber, so not an easy twist on. If it doesn't line up you could heat the tube on the cat and bend to fit, or cut the flange off both and use a rubber hose with clamps.