ok a i have a 86 N/A and i just got a brand new main cat a week ago and ive never checked the pre's and i was thinking of gutting the pres only. my question is will this help? since thier the originals. Also will it sound bad without the pres and just the main and will i get any type of power out of this. Thanx ahead

 

bump need answer

 

I gutted all three of mine with stock cat-back, and I think it sounds pretty good...Still not loud.

 

but is still need to pass emi tests can i just with the main???

 

The pre-cats are only for initial start up.
They prevent that stinky cold engine smell.
After that they are not needed.
If it would pass visual inspection, consider replacing the iron box collector & precats with a header.