03 gmc 5.3 I already cut off the mufler and strait piped it. And it runs alot better.So would it be a good idea to bore out the cats or would the trucks emitions not let it run wright?

 

if you remove the cats there's usually a fine. 10,000 where i live but i would not recommend it if you want to pass emissions it will still run fine but you want the exahust piping so if your driving you dont want back pressure bringing cold air back up your pipes because that can warp a valve. happened to my freinds 99 dodge 5.9 and he was running straight headers

 

you can lose low end torque if you cut the cats off but thats what others have said on this forum you will be ok if you do but like suggested i would use piping to fill the gap or go to your local parts store and pick up a pair of thrush or cherry bombs and weld them in place it will still ahve that loudness but will retain the backpressure needed
i ran straight exsasut manifolds on my car for a week before i put them on my car and it didnt really do much other then the idler pully system became loose and i had to replace it
im lucky i didnt jump timing or warp a valve
also where i live there arent state inspectios and most the time you wont get pulled over unless your goin thru a certain town where thats all they look for
our state law does require mufflers and cats but like i say nobody really checks

 

Unfortunately I live about 30 miles from philly so I do need a muffler that's why I went with a 10 series. Its probally the closest sound to straight pipe im going to get but it sounds nice because its not all raspy. But where I used to live in MD there's no emmisions

 

o well anyway i bet it does sound good im thinking of doing my exsauhst as i only have true dual with thrush tubes under the cab and then after that there are no tubes or nothing so my cab gets kinda exsausty smell

 

I planned on just boring out the cats they will still be connected to the pipes just holowed out. My reason for that is i think they are clogged up not leting the truck breath

 

that will help the truck breath
my cats were plugged horibly in my car thats why i put thrush tubes on it instead
also what type of inspections do they do where you live is it the visual kind or do they actually hook up a emissions machine to the exshuast