When I had the S&S header system installed on my '85 van the muffler shop made up a "test pipe" to replace the catalytic converter.  They welded up a couple of used 3 bolt flanges to a piece of pipe to match the overall length of the converter.  The flanges matched the ones on the converter.  Now I have a choice of running with or without a converter.  I almost always run with the converter in place.  This fix would be easier than hollowing out a converter.
George
'85 Westfalia

>>>Worst case  just get a cat and hollow it out.

>>Does anyone know the part number for this pipe and >>also know where I could buy one?