I'm with babywag on this one...
Loosen up the driver's side manifold to y-pipe, loosen up any connector within the y-pipe, loosen the connection to the cat, all to where they're almost completely removed.
Then see if it fits. The exhaust manifold to y-pipe should in no way be off that much.
Heck, try loosening the driver's side manifold at the head, replace the gaskets, then slowly torque everything down.
Curious... Keep us posted.
1977 Jeep Cherokee Chief
360 w/ MC 4350
All stock but ignition and slightly modified suspection
Original paint, garaged/non-op for over 15 years