Can you and is it ok to run stock cats with headers?

 

only ones you can really do it with is shorties...since they usually reuse the stock Ypipe.

stock cats are 2.25 or 2.5" which is a restriction for most applications. not to mention you'd have to do some creative welding to hook them up. since one cat bolts directly to the manifold collector.

short answer...NO

besides...high flow cats are much better, and smaller

 

One cat is also on the bend to where the pipe goes from a more verticle position to horizontal.

Just get some carsound cats off ebay for ~$60.