Rather than assume I'd do some troubleshooting. Disconnect the flex hose from the fuel line to the fuel pump and insert into a small container of gasoline and see if it pumps from there. If so, do the same at the gas tank, where you'll have to disconnect the metal line and slip a hose onto it into a container and see if it draws from there. This should narrow down where the problem is.

Actually there is an illumination level control in the 22-23 series but it's just hi/lo with a pushbutton, labeled 'Instr'. Off-Parking-Headlights is controlled by the three position headlight switch.

With the fading of the radium paint over the years low becomes barely visible, exacerbated by all the light pollution nowadays.

The 22-23 series dashboard is a most awesome companion on a moonless night on a vacant country road in the open desert west.

So the belief is the whistle was a Packard exclusive feature that began with the '41 Clipper and ended after the '51's -- a ten year span interrupted by the war.

That makes them very unique.

My father happens to have a '42 Senior Packard, no whistle.

Per a quick online search the automatic shut-off gasoline pump first appeared in 1939 but was rather crude to begin with. I'm sure it took many years afterwards for automatic shut-off to become commonplace in the field. I suppose the transitional period could have been particularly confusing as you may not know if it was or wasn't, but back then stations almost always had attendants and were not self-serve, for good reason.

Okay trivia buffs, what year did Packard introduce the tank whistle in their cars and when did it disappear? Was it common in other makes of automobile?

No, I don't have the answers so I can't check your work. It's on the honor system ;)

The car is running 235/75R15 tires, which have a diameter of 28.9". The speedo reads high pretty much the same across the typical 25-60 driving range.

Do all Ultramatics have the same speedometer drive gear regardless of rear end ratio? I do know the previous owner rebuilt the transmission and had at his disposal a parts donor Clipper. (I had to remove the transmission due to an inoperative DD clutch and discovered a mismatched '55 pump and '56 plate, blocking the oil path.)

My '55 400 reads 6mph faster than actual. Any suggestions to correct it?

I installed Retrobelt in my 400. The Aviation style matches the original style. As for length you'll need the long 75" for the front and the short 60" in the rear.

Installation is pretty easy and straightforward on the 55's. I have a '55 Patrician that has original (likely dealer installed) front belts which I used as a guide. The front belts do not intrude into the rear compartment.

Pics (front seat adjusted fully to the rear):https://photos.app.goo.gl/ceCxu5kxnmvsXhe78

My '48 Custom has a rear main seal leak. I have to leave the flywheel cover off to keep the clutch from getting oiled and ruined. I'd like to fix this and my plan is to drop the pan and rear bearing cap to use a sneaky pete to remove the old rope seal.

Rather than trying to stuff a new rope seal in which will probably be an exercise in futility that will also leak, my plan is to insert a split lip seal if there's one the correct size. My question is, what if any is the recommended split seal for this application and are there spacers involved being lip seals typically aren't as thick as rope seals?

On the topic of installing rear drums, I've mentioned this in the past but will mention it again, applying a thin layer of Milk of Magnesia on the tapered shaft, letting dry, prior to installation will aid removal later without compromising the integrity of the tapered fit. This doesn't address your noise problem but can make life easier.

A follow-up on shock absorbers for the '55: I finally replaced mine with good results.

For rear I used the KYB Excel-G 343042 which has extended length of 24.49", compressed length of 15.35", for a 9.13" stroke. Upper mount is stud (S1) and lower eye ring (E1).
(Alternative rear is the Gabriel 82066 which has extended length of 22.7", compressed length of 13.34", for a 9.36" stroke.)

For front, which is where the '55 is unique, I used the AC Delco Advantage 520-284 which near as I can tell is actually made by and identical to the Gabriel 82026. It has extended length of 13.42", compressed length of 8.56", for a 4.86" stroke. Upper and lower mounts are stud (S1).

Compression damping is relatively light in these shocks, with heavier rebound damping. This gives more responsive action with torsion bar suspension, allowing the suspension to absorb and transmit the shock to the other end of the bar rather than convey it to the corner of the vehicle it was received.

I can attest that the old stud shocks are not easy to remove once rusted as it's difficult to remove the nut while keeping the stud from spinning in very cramped quarters. That's the most difficult part of the job. Installation is easy, but removal of the upper studs all the way around is a bear.

The ride is improved as the old shocks had very little damping left and the wheels would hop following a sharp bump. Although occupants couldn't really feel it happening, you could hear it. They no longer do that and I expect traction and control is thus improved.