Bloo

The leak could be literally anywhere. Gravity wants to push the fluid back to those underfloor systems. Are there cup expanders in the wheel cylinders? The wheel cylinders are at the top and can let air in without a visible leak. There probably weren't cup expanders in 1951, but modern era repair kits almost always have them. Over the shorter term, the system's residual pressure valve takes care of this, but I don't think you could expect that to hold for 6 months. Almost nobody would have let the car sit that long as a normal thing back when it was new, and they probably would have never known the difference.

That sure looks like 1937 to me, although I am not 100% positive.

If it were me, I would dunk that bad spot in evaporust for a while, maybe a week or longer. I would want that heavy rust gone, clear to the bottom of the pits and that would take a while. This time of year (in the US) I would probably add heat, as evaporust slows down horribly when cool, and stops completely at 60F if I remember correctly. It would need babysitting, moving it a little as you walk by it because evaporust causes rust right at the transition to air line, and you would have to move it slightly real often to prevent more damage. Acid based cures will skin over and won't get all the rust. Molasses might get it all but I don't know much about that. Once clean, the pits will just hold oil, so no big deal there. You would just have to try it and see if it is noisy. There's nothing you can do about the missing metal, or the hardness. I think it will be fine, but you never know until you try.

Does that mean neither filament lit? If so, you might want to have another look at your test setup or try a more modern bulb. It seems unlikely to me that both beams would be out in both bulbs.

No, they're just holes, but high precision so you don't want to go poking anything through there (just blast with brake cleaner). There is no harm taking them out if they come out easy, but they are usually badly stuck and there is a high risk of damaging them trying to remove them with the wrong tools. Replacements would be EXTREMELY hard to source. It's better to leave them in than risk damaging them with the wrong tools in my opinion. This is also true of the power valve, although it is usually a lot less stuck, and it is easier to find a tool or make one.

There is a small dot of solder all by itself on most floats. It's a hole. Open that with a soldering iron, and close it last with solder after repairing other leaks. When closing it, you'll need to cool one side of the float somehow as you solder the dot to keep it from blowing out. Having that hole open while you repair allows you to solder along the seam and elsewhere without getting blowouts from the hot air inside the float.

$17.61 for a bulb?! Holy smokes, those have gone up. How much is Winky the White Cat?

Well, some people here have had very good results with sealers. I'm not saying they are wrong. Depriving the rust of a ready supply of oxygen certainly slows it way down. In my experience though, anywhere there is even the tiniest bit of rust in steel, it will eventually expand and push loose whatever is painted or glued over top. The whole idea of that bugs me. Your mileage may vary.

I think I'd be tempted to treat it with phosphoric acid. I can't remember ever doing that, so maybe there's some gotcha but I doubt it. The derusted tank has a massive surface area due to the pitting, and will try to flash rust almost immediately. Anything to slow it down a little would probably be a good idea. Gas tank sealers have their proponents, but I don't believe in them. They are going to fall off eventually and cause a big problem. Think about how hard it is to "seal in" the last traces of rust on the outside of a car, even when you can see. Why on earth would it be any better when you can't see? For what it's worth, gas tanks can be really bad and not cause much trouble, particularly if you have a sock filter. On any car that does not have one (except gravity feed), I add one as long as I can do it without hacking things up. Iron and other heavy stuff falls off the sock to the bottom of the tank, and might or might not ever make it back up. The tank becomes a giant sediment bowl. Of course a little will get stuck in the sock, and maybe if there is enough it will plug it. If that happens it's time for a new tank or a fairly invasive repair of the old one. Socks hold back water too, although that may matter less with all the alcohol that is mixed in gas these days.

No. The Olds V8 was solid from the very beginning. "Rocket 88"s were some of the fastest American cars around at that time, and no complaints from anyone about reliability.

36 did have a vertical rib like that.

Don't use brass that close to the engine. It melts. Maybe it could be welded with nickel rod after being heated in a furnace, but your best option is replacement if there is any way. Exhaust manifolds are a special case, as the metallurgy changes a little from the heat, and they take a lot of abuse from expansion, contraction, and twisting from the exhaust system. In my experience repairs usually do not last. I would show it to one of the cold cast iron repair guys first and see if that is a possibility. Next is welding. I believe @Dave39MD had an exhaust manifold welded by a forum member. Last I heard, it was still holding fine. Maybe he knows where to get that done. But just get a good one if there is any way to do so.

Sink it in hot water and look for bubbles (assuming it's brass).

This is typical of over the counter parts store replacement cables, or used to be. They didn't make more than one color in whatever configuration you needed. Just to pull an example out of the air, if you needed something about a couple feet long with one small pigtail, it would probably be red, negative or not. Universal parts. I have seen this so much I don't even look at the color. I follow both cables and see which one goes to a ground. 99% of 12 volt cars are negative ground.

2 balls, and those are the correct places. The big one goes under the accelerator pump plunger. The idle tubes aren't pressed in, they should fall out. There is a special double-d wrench to take the main jets out. It might be hard to get it all cleaned out without removing those, but they are easy to damage. If you can't find the correct tool I would probably leave them in rather than risk damaging them. Same for the power valve. The power valve tool is like a very precision straight sided screwdriver blade with a notch in the middle. If I remember correctly, the main discharge tubes are not removable. Blast every passage out with carb cleaner. Safety glasses would be good. These carbs will spray back at you while you are cleaning passages. Of course there is a risk of not getting all the crap out if you don't remove that stuff but you can probably get it good enough on that particular carburetor. Worst case, you have to take it back apart. The problem that caused it to run over with fuel wasn't any of that stuff. The float and the float valve (needle and seat) are the critical parts to keep the fuel from overflowing.

I don't really have a good answer here, but will say that you should probably post a picture of it. My guess is it is the kind that get pulled on with a spring so it can deal with minor changes in brake pedal height. I have seen those somewhere but offhand I don't recall where. Probably Restoration Supply (California) or Restoration Specialties (Pennsylvania). If it is instead a switch with a mechanical lever that lays on the linkage somewhere, that was a common universal part that even NAPA had until fairly recent times and might still. If not, look at the Flathead Ford and the Street Rod outlets. If it's something unique to Chrysler, I suspect you will need to rebuild it. I definitely would not change to a hydraulic switch.

Have a closer look at this picture.... It is clearly modified. The output post is grounded to the case and a second post has been added at the other end of the diode stack. It is almost certainly positive ground. Occams razor would suggest that it is also 6 volts.

I sent mine to Melissa Klein (Clean Sweep) in Oregon. Works great! Well OK, "great" might be a bit of an exaggeration, because after all, they are vacuum wipers with no booster pump. 😜 All kidding aside, highly recommended.

It probably also had bronze thrust washers under the missing gears, and maybe under the side gears too. Are there any under the side gears now? Buick was using nuts on the shafts on some models as late as 37. The safety wire looks haphazard, and as if it would interfere with the missing shaft. That probably needs redoing. Anyone in here got a parts manual old enough to figure this out?

I am 99% sure that 30s Buicks are all 6 volt NEGATIVE ground.

1940-47 International Harvester, more or less. I wouldn't toss it. Somebody will probably want it. I think it's missing the fan.

The second ring @Oldtech and @rocketraider speak of looks like this more or less. Look at the holes on those little tabs. See how they have a slot that leads over to a bigger hole? If they look like this, you can loosen the 3 screws maybe 1/8" or so, and then just twist the ring to release it. The screw heads will slip through the big part of the holes. That way you don't have to worry about dropping screws. If the holes don't look like that, you will have to take the screws all the way out. It will be obvious if that is the case because the tabs will be narrower, too narrow for the funny hole. Either way be sure you are getting the the 3 little screws on the tabs, and not the adjuster screws.

Most likely yes. Any driveline/drivetrain modifications in torque tube cars tend to be ridiculously expensive up front, with additional hidden costs at the end. Not for the faint of heart (or wallet). Yes, quite a few have done similar things if not exactly this. Look around in the Buick-Modified section on this forum. I believe I have even seen a 57, but I can't swear to it. You would need to decide if you are getting rid of the torque tube or not. If you get rid of it and go to an open driveline, you don't have a rear suspension anymore because apart from a panhard rod the torque tube *is* the rear suspension. Such conversions on Buicks are usually done using a "truck arm" suspension from a 63-72(ish) Chevrolet 1/2 ton pickup, and adding a crossmember to the frame to support it. A different rear axle would most likely be used, although using parts like the third member from a 61 or later Buick in the original axle housing might be a possibility. The Chevrolet "truck arm" suspension most closely duplicates the geometry of the torque tube. If you don't get rid of the torque tube, you would need to shorten it, and have a Buick torque ball grafted onto the back of the 700R4. That would probably mean finding a 4 wheel drive (flanged) version of the 700R4. I don't know offhand if that exists, but it probably does. You would then need to have a machinist make the parts to get a Buick torque ball attached to that. At least that is probably how it would go, as I have never seen a kit to do that. Either way, the 700R4 is going to be longer, and that will affect u-joint angle. On most Buick torque tubes, there is only one joint. In that case it is in the torque ball, and must run straight. Since it has to run straight, it cant have needle bearings, and must run bathed in oil. Some later Buck torque tubes have 2 u-joints, one in the torque ball and one at the rear. I think this is what you have. In this case, it follows the same rules as an open driveline, and the two angles must be the same. Since the 700R4 is longer, the front u-joint angle will get tighter, and the rear will not because it is inside a torque tube. The angle that the engine and transmission are mounted will have to change, relative to the car. That can be mostly achieved by mounting the tail of the 700R4 a different height than the Dynaflow was. This might or might not cause clearance issues at the distributor/firewall, fan/radiator, and exhaust. You might or might not have to rework the front engine mounts. At the bare minimum, the first bend in the exhaust pipes is going to be wrong even if nothing else hits. The shifter would need work too, yes, because the Dynaflow shift quadrant is different. I expect it is the easiest part of the whole deal, even tough I think you will need to have some parts machined. There are probably other things I haven't thought of. I'm with @Larry Schramm. Keep it as built. Welcome to the forum!

Go big. Adding any extra connections in a battery cable is asking for trouble, and shutoff switches are notoriously unreliable. It's also more critical at 6 volts because the current is higher. Something intended for a fire truck might be about right. On some previous thread in this forum I've lost track of, @Matt Harwood identified a switch that has proven reliable. I've not tried latching solenoids. That's an interesting idea. I wonder if the latch mechanism would work on 6 volts?

I'd probably rinse it out with the diesel or mineral spirits, just to get as much residual junk out of the bottom as possible. This overdrive is really early and I am unfamiliar, but I don't believe they have clutches. In any event overdrives are more particular about the lubricant than transmissions. After you put it in the car, make sure the overdrive section has plenty of the correct lubricant in it before you go driving. If the oil has to "flow over" from the transmission side to fill the overdrive, make sure that has occurred. I don't know what "correct" is for this car, check the manual, but my best guess is "Mineral Oil" aka GL-1, and that synchromesh oil would probably also be OK.