The NOS ignition switch does not include a cylinder so I just have to figure out the trick to extract the cylinder from the old switch and insert it into the new.

That was my thought. I'll let you know how it goes. It may be two weeks to receive the ignition switch and I'll have to transfer the key cylinder. Any wisdom on that short of taking it to a locksmith?

I ordered the four pin Gebildet JD1912 What are your thoughts on the best way to wire it with positive ground?

This is the standard diagram.
https://photos.app.goo.gl/BkcaTzAjAj72Brdq6

Looks like Tucson Packard rebuilds them for $200 but are out of stock. Maybe I'll just give them my old one. I found an NOS switch still in the box for $150 -- you're right, not cheap. An under dash relay would be a rather simple addition and are only about $5 so I may go ahead and add it.

Thanks. It didn't take long going from intermittent to not working at all. I assume it's not practically repairable and I need a replacement switch, which I assume are all used, with luck of the draw as to the actual condition.

My 400 has gradually developed a problem where the starter won't actuate. I just get the sound of a relay click (on the firewall) when the key is turned on and again to start. Battery voltage 12.6v. Neutral select switch checks fine but the brown wires are jumpered for these tests.

Working my way up the chain, I'm getting no voltage to the starter solenoid terminal with the brown wire in any ignition switch position and no voltage at the neutral select switch. At the ignition switch I have 12.6V at the battery terminal, 12.6V at the accessory terminal when on, and nothing at the start terminal in any position. Is this pointing to a faulty ignition switch?

BTW, voltage at the resistor with the green wire to the other starter solenoid terminal is 5.6v whether in the on or start position, (12V on the other side of the resistor).

If the transmission was rebuilt with modern clutch materials then Dextron spec ATF is recommended. If old NOS parts were used then Type F or Trickshift, which is a modified Type F.

I've obtained exhaust systems for the '48 and '55 senior Packards from Kepich Exhaust. Had a local old-timer muffler shop install them. No problems. Waldron is another vendor of premade systems.

I do see that the Kepich web domain has expired. Hopefully that's just a late payment and not due to going out of business. Their facebook page is still up.

Waldrons is https://waldronexhaust.com/product/1955-58-packard-v8-dual-exhaust-w-resonators/

The fender mounted power antenna on my '55 400 works, though seems to be straining hard. As far as I know it's not been touched since new so I'm wondering if there's any lubrication point on it that I should address to avoid damaging it. I wouldn't want to strip something out.

The jute or stainless material is supposed to be rinsed out in kerosene once in a long while and pan cleaned out. I've not encountered one where the media was falling apart and don't know why it should unless it was abused.

The advantage of oil bath is that they will run a long time with almost no restriction in airflow, which doesn't increase as they get dirty. They just keep accumulating dirt/sludge in the bottom of the pan. Paper gets more restrictive as they clog up and have to be replace relatively frequently but it's certainly a less messy task.

The paper filters are considerably more costly. (Some in newer cars are an outrageous three figure cash cow for automakers, only available at dealers.)

Some large industrial and agricultural equipment still rely on oil bath filtration but some have gone to centrifugal prefilters with paper secondaries. That takes up a lot of space and for that reason isn't so practical for automobiles.