The earlier pipes were a flat flange. The replacements use the donut to make a swivel connection. The replacement cats will accept the donut. There is a donut that is offset and flat on one side to fit the old cat. I think the Bosal part number 256-049. 

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Mark McCulley
Sent: Friday, July 25, 2014 4:37 PM
To: vanagon@GERRY.VANAGON.COM
Subject: which exhaust gasket to use?

What is the correct type of gasket to use between the J-pipe and the catalytic converter? My J-pipe has a flared end and seems to be made to use one of the donut gaskets. But the cat just has a flat flange, no flare to seal a donut.

-Mark
'87 Westfalia