BigKev's got it right, clearly from the last picture it's a 180 Formal Sedan, chassis 1807 - 138 inch wheelbase, and the 106th of that body style built. Not a Rollson or Derham but a factory body built by Packard (for 1941 they outsourced Packard body production to Briggs). Not a body style for everyone, but a very classy full bona-fide Classic Packard, and a lovely road car with the new-for-1940 356 engine. Engine# should be between CC500001 and CC507697

Six, Eight, Super Eight, or Twelve? I don't know if they were all the same but it would help to know which chassis is in question. I've not taken note of these on late prewar cars, but later the lower flexible sections were simple rubber sheeting which you can buy from any industrial supply house in any one of dozens of compositions, finishes and thicknesses. In the few I've taken note of, the rubber was stapled to the steel panel, though I can't guarantee that is how they left Detroit.

Others may dissagree but I've always considered the Packard V8, though large and powerful, to be a very conservative design without any particular innovations beyond what others had already done, so I'd not think there was any "prowess" for others to take advantage of.

There weren't many engines that went on to careers with subsequent manufacturers or in other appliations; the three that come to mind are the Pierce-Arrow 8 & V12 and the Lycoming V12 that went on to very long careers powering fire engines of Seagrave and American LaFrance (?), and though not the same engine, some of the design elements of the Franklin engines that were modified for a small number of Tuckers, and for a very large number of Korean war helicopters.

Surplus Packard V8s were sold for years after Packard ceased by J. C. Whitney; one frequent application was for conversion to marine applications and quite a few of these still exist. And the selling prices back then were CHEAP.

Tom, the differential on a 32 and up Packard is a hypoid type which mandates use of an EP gear oil, though it certainly isn't required in the transmission or steering gear box. Without it your ring and pinion will scuff severely. Perhaps the corrosion/pitting you saw was from long storage with condensation in the oil? On the half-dozen 34 Packard differentials I've looked at that sat for decades, there was lots of pitting, especially near the interface of the oil and air. Perhaps a straight GL-1 gear oil is a better choice for the steering gear and transmission, these are just straight mineral oils with defoamer added.

A valid comment about the compatibility of some EP gear oils with transmissions/ODs with bronze parts; I've read that same caution myself several times years back. I can only say based on using EP 85W-140 in my R-9 for 2 decades that I never had any problems and the unit was silent.

I owned a 54 Patrician back in the late 50s and thru the 60s as an everyday car (they were one fine car!) and I took a good look at that one. Several things caught my attention. According to the 54 Packard Salesman's Data book, there were three different interior options for Patricians, wool broadcloth, leather or matelasse nylon fabric. Seller states that one was redone in wool and the pattern seems correct though I can't attest to the correctness of the colors, especially the lighter color I also wondered about an engine rebuild after 57,000 miles when, barring abuse, that kind of mileage would just suggest a valve grind. And then another cylinder head gasket replacement? Also the notation about a valve adjustment when of course they are hydraulic and not requiring adjustment -- unless they were improperly set after the engine rebuild. Some questions for the seller but it does appear to be a very nice example of that model. A recent Packard price guide suggests $17,200 for #1, $11,200 for #2, and $7900 for #3. They are a delightful car to drive, and very comfortable.

An earlier response here indicated the Patrician came with "gear start" Ultramatic; that's only true for the very last cars of the production run, the vast majority were simple Ultramatic.

The gear oil that many of us use in standard transmissions and overdrives, steering gear boxes and differentials, as previously noted, is SAE EP 85W-140. If your trans or OD makes noises with this, using a heavier oil is probably just forestalling the inevitable failure and probably further damage will result -- best to find the source of the problem sooner rather than later.

Just looking at the pictures in the 48-54 and the 55/56 parts manuals, it appears that the front crossmember pictured in Kev's 54 isn't used in the 55/56. Too cold to go out in the garage and crawl under the 56 to confirm but it would appear that the 51-56 frames are not all the same in this regard.

Just a comment about the king pin job. Best shop practice is to never use an abrasive hone to resize a bronze (or other) bushing; scrub and clean as best you can but particles of abrasive can and will become imbedded in the pores of the bronze and shorten the life of the fit. Always use a ream; you can buy an adjustable ream from most any machine shop supply house, and individual fixed size reams for various diamter kingpins show up at lots of flea markets, often for a $1 to $5 each.

The additive packages are no doubt proprietary with individual antifreeze formulators and there's no reason to think that all brands have chemically identical packages, but they're formulated to be acceptably the functional equivalent or nearly so. I use the word "package" because there are different metals which require protection from corrosion, cast iron, brass, copper, aluminum and tin/lead (solder) at a minumum and there is no wonder molecule that protects them all. The packages I looked at some years back contained a chemical compound like tolytriazole for copper and brass protection, and inorganic silicates for cast iron, plus other ingredients. Some of these substances (but not the ethylene glycol itself) have a transitory life.

I'd say that they "control" corrosion to acceptable levels but I doubt anyone in the business would ever say they make the solution "corrsion-proof". Dem's strong words.

BTW, my 56 Caribbean still has it's original radiator, clean as a whistle, and to my knowledge as never been serviced. So did my 34 Packard until a few years ago when I decided to recore it based on it's physical appearance, not its performance.