New studs, nuts, and washers are available from Max and Kanter.

IIRC, the nuts are brass to avoid corrosion issues.

I know the washers are hardened and extra-extra-thick, at least for the 288/327. Hardware-store washers, even if hardened, and even if extra-thick, don't work as well.

Note this post from someone who had similar mysterious trouble. The problem was the water pump installation

https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?topic_id=26864&post_id=257100#forumpost257100

I had my starter and generator along with the distributor rebuilt by Buchannan's auto electric in Oakland, CA. They did great work. Their contact info is in the Directory. I also gave them my voltage regulator and they adjusted that.

Having made mistakes before based on "I checked that", though I actually hadn't checked it, or hadn't checked it correctly, it sounds to me like something you think you have checked isn't actually "correct" or "good".

It sounds like that water is getting into the radiator, because the radiator is getting hot, but that water isn't circulating in the block.

That makes me think that the inlet or the outlet to the pump is blocked. Perhaps the pump gasket is misaligned and blocking where water goes into the head. Perhaps as some have said the lower hose is collapsing or blocked. Or - since you put a new radiator in, perhaps there is something at the bottom of this new radiator that is blocking the inlet to the pump, or as some have said, the tubes are blocked.

My engine, which is a 327 essentially the same as your engine, after you start it takes about 1/2 hour or more to get up to "1/2" on the temperature gage, in typical 60 degree weather. That's with a radiator that has been "rodded out" but not recored, and has a few tubes which are clogged.

Are you talking about the rear axle or the rear crankshaft seal?

I believe those engines did not use a rear main crankshaft seal, rather a slinger. There are various issues that could be occuring, look for "slinger".

IF you are talking about the rear axle, there are seal kits available from the major Packard vendors, Max Merrit, use their online search tool for 1940-42 and search for "axle"

Max Merrit

And Kanter
Kanter 1940-50 Packard Parts

There are a few bearings which have been added to the cross-reference on this website:

Packard Parts Cross-Reference, Rear Axle Components, this website

Lucky on at least 2 counts!

I have the "Redi-Rad" so I can play anything I can get on my phone through my radio. But I still listen to AM on occasion as baseball games, etc. Also a lot of "international" music is on the AM and it's actually fun to listen to as well. People do wonder, though, when a Packard drives by with the windows down and Bollywood is playing.

You can just plug the outlet to the heater core and the inlet at the pump side, correct? My understanding is these cars weren't always sold with heaters in the first place.

Packard Valve Adjustment Video by Ross:

Adjusting 1953 Packard Valves - Speedwell Garage

I guess the main question is:

1) What is the problem you are trying to resolve?

I was able to get a lot better sound-location by putting the stephoscope right on the adjuster (well, the hydraulic adjuster in my case) - they move up and down a bit, but not enough to interfere with the sound - and it locates much better to what valve is the problem. Try it!