Many lighters of that era used a special fuse that threaded into the back of the lighter. Can still be bought but expensive. I'd just install an in-line fuse. That still doesn't fix the polarity issue though.
https://www.ebay.com/itm/NOS-CASCO-L3c-L3-automobile-Cigarette-Lighter-Fuse-1950s-buick-and-cadilac-/163527776696

These King-Seeley gages use a scale of 10 ohms full to 70 ohms empty with a few ohms variation. The parts book lists 4 different senders for 57-58 L models. These gages also use a voltage regulator for the fuel and temp gages.

Note- I just edited my post. I had mistakenly written 0 ohms where it should have been 10 ohms.

The Studebaker forum has an ongoing thread called 'Studes in Roadside America', with over 7,000 entries. A recent one mentions this Packard and another poster provided a photo of it with the back glass shattered. Charles Starkweather stole it from the Wards after killing them in Nebraska. He was captured in Kansas I believe.
It all made me curious if that car has survived to today. Anybody have any history on it?

Love that show! I usually record it every day. I do remember seeing the '55 Clipper, and a few '52-'53 Packards, and early '50s Studes. I really enjoy trying to find the locations on Google Streets. Once in awhile I can identify some buildings that are still pretty much as they were 60 years ago.

There was another factor not mentioned in all books. Chrysler bought the Briggs body plant about this time and couldn't/wouldn't do any more Packard stampings.
Packard even investigated the purchase of previous years Lincoln stamping dies but were unable to acquire them.

If you can take service bulletin 325 at face value, all the old retainers should have been removed from stock and only the hardened ones were available after that. If they pass the 'file test', they're hardened.

Perhaps chrome mast jackets were lost to the Korean War. Restrictions certainly were placed on the use of nickel and chrome during the 1951 model year.

That information is in a shop specifications manual published by bearing manufacturers. Most auto machine shopss will have this book. Trouble is, if a certain manufacturer no longer makes bearings for a particular engine, they don't put the specs in their book either. By comparing three different books, I think I have pieced together the specs you want. Try main line (tunnel) bore 2.936", and Con Rod big end bore 2.220".