spark plugs and wires
You may want to go with the plugs for a 5.2/5.9 magnum engine. They are a 5/8" hex but have the same thread and reach as the 13/19" hex spec'd for the LA engine. This will make installing/removing plugs with headers much easier. I am running Autolite 3923 which are one heat range colder than stock.
Also, get cut to fit wires with multi-angle boots. This will allow you to route the wires the best way to fit around the header tubes. Typically cylinders 5 & 7 work best if the boot is 90 degrees and you route the wire under the tube.