options on gutting cats
 

1991 ZR1 was wondering if there is any addvantage buy gutting the cats ,like louder exhaust, and will it set off any codes, or is it a waste of time thanks jamie

Louder = yes, a bit
More power = yes, probably worth 10hp or so
Codes set = no
It's a major PITA to remove the manifolds and an even bigger PITA to put them back on. If I were you I'd just spend the extra dough and get a set of headers, you can sell the stock parts to recoop some of the cost.

Exhaust system pressure drop
 

Take a look at the following article: http://www.zr1specialist.com/HAT%20W...kpressurea.jpg

Changing the mufflers will give much more power gain than gutting the cats. Gutting the cats would be a large effort for very little gain.