Just wondering if anyone has any experience with the Delco-style regulators from Quality Power

Quality Power Voltage Regulators

You might try posting in the Packard Club forums as well:

Packard Club forum, driveline, rear axles, etc.

Where is it located?

I saw this on Etsy, looks similar to your part. 4.69 ratio it says.

1931 Packard Ring and Pinion

Probably other people know better, but these two companies are in the business of manufacturing new ones:

Old Far Manufacturing

Rempco Vintage Vehicles

Here's Ross with a 3-on-the-tree 1953 Packard Clipper (turned into a pickup truck)

(and a couple of Studebakers, too)

Speedwell Garage 3-on-the-tree

Coming up (maybe, someday) is promised a video where he talks about how to use the overdrive.

But here is another video from someone with a 1948 with overdrive

Overdrive 1948 Packard

and a nice breakdown of the R11 Overdrive

R10/R11 Overdrive

Hi There,

I don't know anything about 16" tires, my own personal experience is with the Hankook H724 235/75R16 thin whitewalls, which I like. It looks like from what I've read so far there is no "modern" equivalent of a 6.00-16 tire.

Here is another vendor which has some interesting 16" choices, again which I have no personal experience with.

Lucas Classic Tires

Not that I have any experience at all with this vendor, but they do list various 16" tires, not sure if those sizes apply to any Packards:

16" tires

I remember seeing these posts, though I don't think this bar was ever attached to the frame so the car could be rolled around, but that would perhaps just be some C-clamps and chain/rope/cable:

Engine Support, Part A

Engine Support, Part B

Instructions for adjusting the bands are here:

Ultramatic Service Manual, Part 1

See Page 34. Torque the adjusting nuts to 20 ft-lbs, then back off 1 3/4 turns, then tighten the lock nuts (to 20 ft-lbs also from what I gather) (that's the way i read it, anyhow)

This is part of the larger collection:
Ultramatic Service Info

Also a nice diagram on Page 16 and instructions on page 37 here:
Ultramatic Serviceman's training manual