I did a magnum swap in my Barracuda in 2012, ran factory pcm, no cats. The way I tricked the pcm was to use a non foul sparkplug adapter in down stream O2 hole, then screw down stream O2 cell in. What happens is the down stream O2 cell will report a change but since it is not in the exhaust stream it will not read correct. The pcm sees a signal and never knows the cat is gone. I also did this when my cat on my 2000 dodge dakota went bad, removed cat straight pipe, used this trick and presto no codes.
