Chrysler had a recall for plugged catalytic converters.
This happened to my 1995 with a severe loss of power.
The 1996-2003 passenger side 5.2/5.9 Magnum exhaust has a undrilled boss where 1992-1995 models had the EGR feed tube connected.
You could drill a hole there at that flat spot to measure backpressure, then drill tap and plug.

On my 1995 5.9 with stock exhaust the backpressure was 7 psi at full throttle and 4000 rpm with 60,000 miles on the odometer.

The cat converter plugged around 100,000 miles.