Bloo

Reliable compared to what? That was a period in time when reliability was something people reminisced about, wishing they still had whatever they traded in. If you are going to buy something from that period, you could do a lot worse than a Turbo Chrysler. The 2.2/2.5 engine is bulletproof, and the Turbos were hands down the best of the Chrysler front wheel drives. I don't know where they rot. That isn't a common issue where I live.

How many exist?

Well... Looks like you are taking the sending unit out again... It is either hitting the top, or the float is sunk, or the sending unit is just plain bad. 22 ohms should be something a bit above half, so apparently your dash gauge is doing what it should.

The one in the second link looks good. (I don't have enough headroom for it, but it looks good.)

If I had a nickel for every time I have seen a battery switch causing trouble....... Good starting depends on clean tight connections, and keeping the number of them to a bare minimum. Battery switches fly in the face of this idea. Some of us really do need them on our old cars. I don't think any of them are even short term reliable, let alone long term reliable. Ok, maybe one of those enormous Cole-Hersee things they used on fire trucks would be ok, but even that adds connections and another cable to the system. Also, its the size of a cantaloupe, and where would you put it? I think that "Green Knob" switch is the best thing available because you aren't adding any more cables, it can be taken off easily, and you tighten the connection by hand, so you know it's tight. I want a switch on my Pontiac, but the area under the floorboard is tight. It either needs to go there, or I would have to lift the hood or crawl under the car to reach it. The green knob, as built, doesn't fit. I was in the midst of modifying one to fit in the available space, and I broke it. Guess what? It isn't brass. It is some cheap white metal, probably zinc. They had just painted or plated it with something to turn it yellow. Also, the cross section of the metal where it broke was pretty thin. I thought "i'll just buy a brass one". Nope. I don't think it is made in brass. I looked everywhere. If you read the fine print, it always says "brass finish" or something similar, or it just doesn't say. If any of you know where to get one made of actual brass I would love to hear about it.

Thats what I would do, too. Align the manifolds to each other in such a way to minimize the error, and then have it machined.

I agree, Roger is on the right track. The ignition cant really be off while cranking, because the Buick autostart system does not require you to touch the ignition switch to crank the car. I would check the battery voltage while cranking. I would also check the voltage at the starter (between the battery cable post and the starter case) while cranking. The cables are the main suspect in a case like this, followed by a weak battery. I believe the positive cable goes right to the starter post, and the rest of the electrics also connect there (that would include the ignition). Does your negative cable go to the frame or the engine/transmission? If your negative cable goes to the frame, there will be a third cable or strap running from the frame to the engine/transmission. It needs to be as big, and as good as the other two.

That would suggest that the throttle shaft or bushings are worn out. If so it may need to go top a specialist. When you have it off of the car, pull the throttle arm in the same direction the return spring pulls it and close the throttle slowly. If a throttle plate is scraping the bore before it closes, the shaft or bushings are going to need work.

And if the carb does need work, get the kit. "Remanufactured Carburetor" was, for a couple of decades at least, just a codeword meaning "horse puckey" or "someone else's problems". Unless you already have such a carburetor on your car, the one you would be giving away as a core is 10 times better than what you would be buying. If you do not have the ability to overhaul it yourself, or don't want to, find a specialist who is very familiar with the 4gc to rebuild the one you have. P.S. Carbking (2 posts above) has rebuild kits, very good ones.

Someone may have eliminated it;

Yep, thats what it is.

On my Pontiac, yes. On Summershandy's I see the negative cable goes straight to the block rather than the frame. That lessens the importance of the third cable somewhat (but it does still need to be good).

If in doubt, don't take it apart.

You guys are right of course about the lead debate dating much farther back. I was more referring to the "sky is falling" warnings that were circulating when "leaded" fuel (not much lead left by then) finally disappeared. Everyone was gonna need hardened seats installed in their heads, or need to use smog-era heads with the induction hardened seats, etc. There was some discussion in those days about guides, but it wasn't the main thing. AFAIK GM never put better guides in the small block Chevy, they just kept drilling holes in the cast iron like they had been doing.

This was a hot topic in the late 80s and early 90s. It was thought that since the automakers were induction hardening valve seats in the unleaded era that it must be necessary. However, it turned out later on that the fears were overblown. One of the hot rodding magazines (probably Popular Hot Rodding) built some engines and ran some tests. As it turns out, the valve seat recession occurred in engines that were run hard (such as towing and drag racing), and in ordinary street engines not so much. Hard seats are added to earlier heads by machining out the old seats and installing an insert. It is a rather critical machining process, and if you get it wrong, a seat can fall out and hold a valve open. That would most likely cause catastrophic engine failure. It happened quite a bit back in those days. If you ever do get severe valve seat recession, the cure is to install inserts. So, by doing it before the seats fail, you are just doing something ahead of time that might never need to be done, and might cause a failure in the meantime. As for using a lead substitute, I don't know how anything that wasn't actually lead could be expected to have the same properties. Also if it did help protect the valves, how would you know? Yeah, anything can fail, but there is no way I would take that engine apart because of the valve seats.

Voltage regulators regulate by vibrating points. It is normal for the voltage to have a little instability. I'm surprised you can see it going to zero though. What kind of meter are you using? My digital ones freeze up when I try to use them on my 6V Pontiac. If you can actually see what the voltage is, check it against the book. It might be low. I suspect it should be around 7.5 volts, but check the manual. Generator systems don't charge much at idle, if at all. Thats normal. I see you have an original style battery. You can check that with a hydrometer to see how charged it is. It will also show you if one cell is not getting charged as much as the others. That would indicate a battery defect. If the battery is just not getting fully charged, turn the voltage regulator voltage up 0.2v from where it is and drive it a few days. Then, check it again. Driving habits matter with generator systems. A guy who idles in traffic a lot will need a higher setting than someone who drives mainly on the freeway in daylight.

Broken AC wont make the car overheat, quite the opposite. In the 70s it was pretty common for owners of cars with AC to have to shut it off on the hottest days, at least on long uphill pulls, to keep the car from boiling over. Everybody wants AC now. Back then, not so much.

My 1936 Pontiac has it in all windows (the laminated stuff with the clear goo in-between 2 layers). Maybe it wasn't standard equipment on all cars yet in 36, but was available. I would expect tempered glass instead of laminated glass in the side windows of a 50's car. The windshield would still be laminated.

A recent thread about Totem Pontiac, with locations, is here: https://forums.aaca.org/topic/328984-totem-pontiac-liscense-plate-frame/?tab=comments#comment-1896623

No.. well... sort of.... It gets magnetized every time you use it. What they are telling you makes no sense. Now, there is a device called a "growler" that is like a giant demagnitizer, but you don't use it to demagnetize the armature, you use it to find a shorted winding on the armature. If you find a shorted winding, the armature would need to be rewound or replaced. Go get it and bring it home.

I tried to braze a chicken, but I couldn't get it hot enough to melt the brass, it just kept catching on fire. Oh well. My Grandmother used to say "If at first you don't fricassee, fry fry a hen!"

This one? https://newyork.craigslist.org/jsy/cto/d/chester-1951-plymouth-concord/6925452593.html

Probably a red plastic thing that says "LITE" and has a cream colored knob on it. It clips under the dash, usually on the left. IIRC they still had them at NAPA in the early 90s, and maybe even today.

I thought the roadster was a one year only deal. Could the car in the first post be a 49 instead of a 50?