i thought that the glass packs where 12 inches long.

 

Let's clarify some issues on this post. GP over CATS...GPs won't last as long with the high temp exhaust flow. Here's what you do. Cut a square hole in what would be the top side of the CAT (not visible from the ground), take out the honey comb crap, and weld it shut again. Or Straight Pipe. I had a straight pipe and flowmaster on an old '85 IROC...perfect exhaust sound. Rumble but not loud.

 

I was going to suggest cutting cats in half at the welds then clean them out and weld them back together. Reinstall and in a week or two they will look factory even if someone was to crawl under the truck like our troopers sometimes do and really inspect the truck.. But again wont that mess with the computer ect.. I know it should help on the highway but won't you loose bottom end grunt for pulling? I have always been told that you need so much back preassure for an engine to run "effeciantly"
Just my 2 cents on the subject.

 

i did my exhaust the other day.. removed the large muffler bent some 3 inch pipe flared each end and welded it in.. kept the resonator in-front of the muffler and the one on tail pipe.. it will do until i decide to bend up some dual tail pipes... has a nice deep grunt