How do you hollow out your catalitic converter on a 93 Chevy Caprice?
You should NOT do this. It is illegal in some states. This also
can cause fires to start and endanger you.
Just get a free-flowing, universal cat from Summitt or some
other mail order place and you're both legal and NO loss in power
from having a hollowed out one. There is NO difference between a
hi-po cat and an open pipe.
(Added to answer) - I agree with this answer. To clarify, it is
illegal in all states. If you have emissions testing in your area,
you will fail.
Also, I took the cat off my 92 and actually lost about 2 mpg and
noticed absolutely no performance gain. Don't waste your time.