I am taking my Y pipe off today for easier access to servo, I want to know if I cut out the 2 cats and get a section of pipe installed in place.

Will the sensors sence the difference?

OR....

Should I just leave the cats, and go 3 inch to the 40 series flow master then dual 3 inch back over rear end and dump it there?

 

A code will be thrown but will not affect performance. A tuner can delete that problem. Getting rid of the cats reduces back pressure but also increases flow. There is a threshold and adding bigger pipes will not yield more power with the stock cam and intake. Just do 3 inch to the muffler then 2 1/2 dual out. Goin bigger will reduce back pressure and this will kill ur low end torque. You only wanna do that if you install a cam with more duration and a high stall converter.

 

Well I had a spintech muffler installed 3 years ago and the guy left everything stock to the muffler and the muffler is 3 in and dual 2.5 out...He ran the pipes over the rear end and when the arch curves straight down I had him cut it off.

So pretty much I have what you said, the other day I cut the pipes after the muffler off and installed 2 - 2.5 to 2.125 adapters and then 2 chrome turn downs and aimed them out torwards pass side.

Louder, but not sure if it helped.

Someone told me that you have to 11 inches after the muffler for back pressure - IS THAT TRUE?