I had the same problem with the manifold cracking. Mine was caused by 
missing screws holding up the heat exchanger, it caused stress on the 
manifold untill it broke. If your's broke twice you ought to doublr 
check the exchanger mounts and the tin around the manifold.
 When it happened I was told the part was un 
available so I had it welded back together, no problems yet.
PS mine is the california type as well

. This is the second manifold that has broken in two in the same
> number of years. I belive it is made of cast iron. The exhaust system is
> equipped with an O2 sensor and a cat. The exhaust ports are rectangular. The
> exhaust system is California based meaning that the manifold is peculiar
> only to those exhaust systems equipped with the sensor and cat. A
> passenger's side manifold will not fit. Nor will those from the 49 states or
> Canada.
> 
> If you have one or know of a place where I can obtain one, please e-mail me
> directly. I will pay for shipping.
> 
> 
> Thanks - David Carment '82 Westy - Vanagon list member since the summer of ' 94.
> David Carment
> NPSIA - Conflict Analysis Stream
> Carleton University
> Ottawa, Ontario
> K1S 5B6
> 613-520-2600-6662
> fax:613-520-2889
> 
> 
> 
Charles F. Webb
http://www.teleplex.net/cwebb
Freedom Weekend Aloft- Memorial Day Weekend
http://www.teleplex.net/fwa
81' Westy *Gabby*
864-439-1847
Duncan, SC