Dan Hiebert

You can theoretically clean everything up and get it going again, but once any of the mated surfaces (gears, bearings, bearing races, etc.) become marred by rust, they will deteriorate much quicker, and be really noisy.  Even if not pitted, the discolored spots metallurgic structures (probably not the right term) have changed, and they'll wear differently.  I would echo that it is not worth restoring.  It would be far easier and probably less expensive to find a good replacement unit.

Couldn't afford white letter tires when I was a teenager.  So I went to the JC Whitney catalogue and ordered a white paint stick and filled in the letters on the black wall tires by hand.  Looked OK driving down the road.  Had to re do it about once a month but I had plenty of time and energy to do useless stuff like that back then.  And they were cheap  wide oval type tires. 

I'll go out on a limb here, ready to duck and cover...long-ish story.  I worked for 32 years in an agency that grew from 3,000 to 19,000 personnel with a fleet to match.  28 years of that was in supervision and management with fleet, purchasing, and safety responsibilities.  How we bought tires evolved over the years but was never a "lowest bidder" deal.  21 Sectors across the U.S., and all of them did their own tire purchasing thing, following Federal purchasing regulations, of course.  So, it depended on each Sector's budget.  Some Sectors are sexier than others, so they get more funding, and the Sectors that didn't get much money had to scrimp, usually on tires.  As noted above, cheap tires are just that, cheap.  Didn't last long, tore up the vehicles they were on, etc., but we'd get tires that were hard as hockey pucks that didn't get flats very easily, which was our main concern.  Can't catch bad guys with flat tires on your cruiser.  We'd get good tires for the highway, but vehicles that operated out in the willywags would get something from the truckload sale.  Can't count the number of times I drove a vehicle with two or three different size tires on it the first few years I was in.  That evolved over the years to buying the best tires we could for the conditions we work in and/or under.  We'd deadline a vehicle we couldn't get the right tires for until production could catch up.  To shorten the story, US Border Patrol seems to have a share in keeping Goodyear in business.  BP has at least 20,000 vehicles of varying types, most easily put on 100K hard miles per year, and are kept in the fleet for at least six years, but usually until the wheels fall off.  That means a lot of tires, and just through pure experience, we found that Goodyear products - heavy duty (10-ply), off road, highway, pursuit tires, etc., perform and stand up best for the agency's needs.  Personally, I don't buy Goodyear simply because I can't afford them.  The last few purchases we've done well with Coopers for my truck, and Uniroyals for the wife's car.  The old cars get tires from Coker.  If money wasn't an object, I'd get Goodyear stuff for our newer vehicles.

I love the honesty.
 
When I was 17, I had a 1969 mustang fastback .... base model 351 2brl/fmx transmission. I got 22mpg with the car.
I installed L60-15 tires on the rear. Had to use air shocks to get the body to clear the tires. .... I do not remember the brand .... were raised white letters.
 
I had the yellow traction bars mounted underneath & a 7" pro stock hood scoop on front. .... just the style of the times. .... makes me cringe today thinking of it.
 
As a 17 year old kid I thought it was cool ... today I think I would be embarrassed to share photos of it.
   

You can theoretically clean everything up and get it going again, but once any of the mated surfaces (gears, bearings, bearing races, etc.) become marred by rust, they will deteriorate much quicker, and be really noisy.  Even if not pitted, the discolored spots metallurgic structures (probably not the right term) have changed, and they'll wear differently.  I would echo that it is not worth restoring.  It would be far easier and probably less expensive to find a good replacement unit.

No it's too rusty...all the parts will need to be replaced because of pitting including the mainshaft.
Find another one.

The tire ads I remember were all about traction, mileage, and wear.  Usually not all at the same time.  What stands out are the Tiger Paw ads when those first came out, with the tiger's paw coming out of the tread gripping the road.  I also remember "Uni", "Roy", and "Al" touting Uniroyal tires.

That box is indeed the horn relay.  That one unsecured wire connector, from the near horn, we can see should be attached to the one lead that has nothing attached, that we can also see. Looking at the relay directly it'd be the upper left one.  As harmony notes, there may be a reason it is/was taken off that may need to be chased down.  Keep in mind there is no power to the horn circuit on these cars when the ignition is turned off. 
 
Spitballing here, but that bare section of wire at the horn end may provide a clue, perhaps grounding on the horn, so the/a PO just unhooked it rather than fix it.  Part of the clue also being that only the one horn wire looks to be unhooked.  The power to the horn circuit goes through the ammeter, so maybe either the horn was sounding or the ammeter wasn't working right due to that ground / short.  

My personal thoughts on whitewall or black wall tires:
 
In 1938 the Chrysler was a fairly premium model. People who were pretty well-off was likely the target buyer. The bank manager might be an example. I like to think they would probably be more inclined to pay a premium for whitewalls. 
 

 
The Plymouth was the low price entry level model in the Mopar line up. The shoe salesman might have been more likely to buy one. Less bling. Fewer features. I tend to believe they would be less likely to pay extra for whitewall tires. This is why I have equipped my cars as such. 
 
 

The small hole is the bypass, do not enlarge it.  No thermostat, RTV, etc tells me someone had a cooling issue before you.
 
Have the radiator flow tested, you can use the FSM method if need be.  Bet it's plugged up.  My 51 can idle all day long in 100+ degree heat and not have an issue.  Even before the electric fan conversion.

3-26:
Out running some errands.  Stopped at the Bluff Country Co-op for some goat milk and a few other things.  Man I tell ya it felt good to drive the Meadowbrook.  What a cool car!  Got some strange stares as not many people around here drive a rusty early 50s car.  Actually, I think I'm the only one! 😂

Right about now is when I really enjoy you'uns getting your cars out and about.  Provides inspiration, we got 8" of fresh snow today (was supposed to be 3"), so all of you who can get your cars dusted off and out on the road is awesome.  (FWIW, snow here through March and into April is normal.)

The only glass on these cars that isn't flat is the rear window.  Any auto glass shop should have scads of flat stock that they can cut you a new one from.  Most don't have the right patterns any more, but they can cut a new one from your old one, or a cardboard pattern.  It's all laminated safety glass, too.  Would most likely be less expensive than ordering from somewhere online, to boot.

The only glass on these cars that isn't flat is the rear window.  Any auto glass shop should have scads of flat stock that they can cut you a new one from.  Most don't have the right patterns any more, but they can cut a new one from your old one, or a cardboard pattern.  It's all laminated safety glass, too.  Would most likely be less expensive than ordering from somewhere online, to boot.

That's a good question.  I'd say it depends on how bad the replaceable parts are in, once you take them out and inspect them.  Those carb kits are hugely expensive and most of the pieces you never use since they fit a few different models.
My car has the Carter B&B EV1.  I have 3 of those carbs and I bought one complete rebuilt kit. I was shocked at the landed price of that kit.  So for the other two carbs, for most of the gaskets, I reproduced myself.  The only part I really couldn't revive was the accelerator pump and the dashpot pump, on one of the spare carbs.  If you get lucky, sometimes the leather on those pumps will come back to life after soaking them in a fine oil.  I used sewing machine oil.  As for the tiny flat redish/orange washers under some of the jets, etc.  Those are pretty tricky to reproduce with a punch, but here in Canada we have Princess Auto, which I believe is similar to Harbour freight for some stuff.  You can buy a variety pack of tiny similar washers for under $10.  They work fine.
I was missing one of the tiny steel balls in one of my carbs.  It is 5/64" diameter.  Mike's Carb, wanted about $20 for that ball once it landed with all the taxes and shipping.  I went to a local bicycle shop and they had a drawer full of them.  The guy at the counter asked how many I wanted.  I said I might as well get a few while I'm here, incase I drop one.  NO CHARGE!!
 
So I suggest you improvise, be creative, and shop around. 

As far as I know the 23" 218 & 230 will swap out with no problems.
There are differences on the 230 crank where it will have 6 or 8 bolt holes for the fluid drive transmissions .... so if this makes sense.
 
You can pull a 218 & install a 230 in it's place.
 
Same time depending on your transmission .... You can not pull a 230 & replace it with a 218.
 
Now if you have a straight up manual transmission, they do not care if it is a 218 or 230.
 
The 218/230 share the same block & pistons, head. The crank & rods are different ..... A 230 is a stroked 218.
 
The 230 just simply offered another mounting option for transmissions that the 218 did not offer.
Or you could say, the larger cars with the fancy transmissions, only came with a 230 .... 218 was not a option in those cars.
 
The 230 will be a fine replacement for your 218.
 

Hbpaints' radiator support is oriented correctly, but it may not be installed correctly.  It should be straight up and down, not canted forward as this one is.  The car does not have an original radiator, which may provide a clue.  The support (frame) is one rigid piece, and while it can theoretically be installed backwards, it would be apparent it is not right as soon as you start trying to hang any other parts on it.  It does look rather beat up around the top, too.  I notice in the bottom photo, at the right of the support where it meets the inner fender, that it is further back than it should be.  This leads me to think the support is not attached to the front cross member correctly, or even not at all.  If you look up into the wheel wells, there should be three body bolts per side (at the front edge of the inner fender) that attaches the inner fenders directly to that radiator support.  If they are not there, or perhaps moved to accommodate the wrong position of the support, there's and indicator of your problem.  Those bolts on the outer top of the frame that attach the top of the fenders are correct but can still be attached that way with the bottom off kilter.  The bolt holes in the cross member to mount the support are oblong, but I don't recall that they're oblong enough to cause that much offset, they're only supposed to accommodate adjusting the whole doghouse to or fro fractions of an inch.  There's no telling why, but there it is.

Looks more like a part that was removed and saved. 

Indeed my old Mopars are therapy cars. I get as much enjoyment from driving them as I do repairing and maintaining them. Its rewarding and somehow fulfilling to keep these old cars in tip-top shape, driving them regularly. The world is a happy, trouble free place when cruising around in an old car at 25 mph. You see the sights and the enjoy the smells. Like seeing the world through rose-colored glasses.
 
I really like Sunday morning summer cruises at 6am. Before it gets hot. Head out, grab a drive-through coffee and cruise. Stop maybe for a photo op or shoot a little You Tube footage.  Maybe Friday after work, get some take out food. Head to the park overlooking the river with Momma.  Eat in the car, enjoy the sights. While the sun sets. Its hard to beat.
 
I am in my happy place in and around my old cars. I am fulfilled.
 

 
 

Absolutely, she should be designated with that status.  I think we should get special licence plates like collector plates, and get a discount on insurance.  It would cut down on accidents due to road rage.
 
I drive my 1930 Hudson (Surmod) almost everyday, except when it snows or it's icy during the winter months.  Then they cover the roads with salt and I park it until we get a heavy rain to wash all that salt away. Before I bought Surmod, Harmony, my '48 Windsor, was my pleasure car.  But since I have Vintage plates and not Collector plates, legally I'm only allowed to drive her on special occasions.  Anyway I got her out for the first time this year a couple days ago and it felt soooooo good and relaxing.  Like you said, all the problems in life seem to evaporate, when you're behind the wheel.  The entire time I'm driving her, I can't wipe the smile off my face. 
 
It's also very rewarding driving the old relics after those long winters in the shop wearing lined coverall and scraping knuckles, and figuring out how to approach the next project.  That process is therapy in itself.  Then the payoff is when you firing it up and go cruising.  

Mmm..."parts porn"...

I Used to love to drive. I could go on a road trip on a moments notice without notice.  I would occasionally get off work and drive to the beach just cus.
 
The last couple decades my passion for driving diminished to it just being another necessity.  As cars "Improved" I lost interest in driving.
 
Enter Jacquiline.   I love driving Jacquiline.  Driving her makes me Mentally relax, Physically relax,  and happy so I suppose emotionally relax. All is okay with the world.
The feeling of mechanical connection with the wheels, breaks, Clutch,  and engine are calming and I feel in control.  So much more than my Subaru, which was like driving a sensory deprivation chamber.  I would rather drive Jacquiline to the point I sold my Subaru and Jacquiline is now my sole source of transportation.
 
Does she count as a therapy car?  To me she does.

Interesting, when I had the machine shop redo my king pins I just took the the kit, ACDELCO 45F0025, to them and had them do it.  They reported no issues and it's nice and tight.  But I too them the upright and the spindle, as an assembly, and had them fit it up.

Anytime you take an item to a machine shop, you should carry the component the machining action is intended for proper fit.  The machinist will then know exactly what he is working with.  Lesson learned I am sure with the aftermarket king pin diameter...maybe for a small tweaking fee the machine shop will adjust the initial job for the correct fit.

Since you just rebuilt it, I'm sure you know how it works. And ill assume you shimmed the worm gear bearings snug. Turning the adjuster in, lifts the sector to mesh the gears tighter. ( if i remember correctly) It's best to lift the front wheels off the ground so you can feel how tight it is. The play will be in the sector. The round gear gets end play and general slop on the pin. All you can do is tighten it up as much as is bearable, then live with it. Sectors are available and are expensive. Don't worry thought, there isn't much that can catastrophically fail.