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2x20watt AMP IC ordered and FM radio IC ordered. Sadly to get the best prices on these they are coming from mainland China (7-21 days shipping time). So once those arrive I can start putting the circuit together.

The circuit should run on 6v-14.4v and if put in an external plastic housing , that can be hidden under the dash which will leave the existing radios innards in place. Also it should be ground isolated, so the module so it can be used in -/+ ground applications. Red to +, Black to -, regardless of ground polarity.

Hopefully it will just be a matter of disconnecting the original control wires in the Packard radio, and attaching the wires from this new radio, and then running through a quick setup routine to calibrate the unit for the controls.

Obviously the AMP circuit will be able to put out more power on the 12v cars than on the 6v cars. But at 20watts, or even ~10watts on a 6v application, it should be plenty enough to drive the original low wattage speaker(s), or a low-power dual-voice coil replacement. There are other higher wattage amp IC's available, but to start with, I think this is in butter zone for the original speaker(s).

Once I get the base circuity working, then I will look at layering in the Bluetooth circuitry.

Just started the Packard radio in my Project blog, so if there are questions about reconditioning the original radio, this might be useful:

https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?topic_id=13999&post_id=159812#forumpost159812

Radio IC's showed up. There were inexpensive, so I ordered two of them to play with. These chips are unbelievably compact. Just for scale, here is picture of them (two) next to a normal size house key. Soldering these is going to prove interesting. But I plan to solder some headers on to them so I can plug them into a breadboard for the prototyping. Lucking I have a soldering station that can do very fine solder work.

But i think I need to get one of those swing arm magnifying glasses!

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Get two magnifiers -- one to help the other. Another reason I dislike surface mount boards and components. They are basically throw away as far as any field repair is concerned -- or at least they were after you tried a field repair -- even if you could see the pads and had the right soldering equipt.

Can't tell from the photo if the solder goes in the notches or the pads just inside the board edge. Molex makes some surface mount edge sockets that I believe are available in single or at least small quantity. Wonder if they would have something that might work.

Howard, these are "development breakout boards". Basically they mount those million pin ICs on a small board with some of the needed external components so you can quickly wire them up and test the functionality.

Those notches correspond to the 1/10th inch spacing on many headers and also breadboards. Alot of people simply attach wires at the notch locations, but I figure adding header strips at the locations would be easier. The header strips come in 100 pin length. You break of the length off you need, and the positions the strip in notches then go down and "tack" them in with some solder. This then turns that board into pretty much a DIP configuration that can be plugged into a breadboard for easy experimentation.

The bottom side of the board has larger solder pads around the notches. So not so bad, but still a lot of detail work. Much easier than trying to solder to the pins on the IC itself which is an SMC.

Very fine solder, and a pin point soldering iron and a lot of magnification hopefully should do the trick!

YOU GO Big Kev!
both my radios are rooting for you.