A followup here. Cat was fine, you can shine a light from one end to the other on a new one. Cut out carpet around accel pedal (not an issue). Refurbished K&N airfilter. Checked intake valve, worked fine. Followed air filter body away from engine and noticed it ended as smaller plastic hose/fitting that exited the engine compartment. Pulled off the last plastic fitting that extends from the air filter housing. Truck ran noticeably faster (up to 70 mph now). Next is cleaning the intake plenum and fuel rail when I get the valve cover gaskets replaced. One step at a time...