As Howard (HH56) suggested, the mechanical items are not the same but it is the same system so the conversion would be identical and have the same requirements for any model. You would need to be sure you had senior parts.

There are several in the Classified Ads of my Packard / IMPERIAL page but they are the 1951-1952 type. Not sure how they different to 1953!

I converted my 1940 110 to overdrive which I can't image is much different in the basic concept to a senior model.

It required, of course, finding, rebuilding and installing the overdrive transmission and its added supports, cable, wiring, relays, kick-down switch and all the obvious stuff but it also meant shortening the drive shaft and replacing the rear end with the proper ratio for use with overdrive. This latter isn't absolutely necessary but it will make adding it a bit better for highway driving as the non-overdrive rear end was something of a compromise for keeping the RPMs somewhat reasonable at speed but sacrificed the power from a stop. On a junior it made a big difference but maybe not so much on a senior!

This was at least forty-five years ago and cost several thousand dollars but would cost far, far more now especially due to the fact that parts that were difficult to find then will be much harder to locate now!

Replacement hoses are available specifically for these cars through the Packard parts dealers. If Kanter doesn't have them, I know that Dwight Heinmuller does although his are not too authentic.

Did you confirm which Carter it is? I could tell by looking at it that it was Carter but the number stamped on it is what determines the model to be sure you're getting the proper one for your car.

On the hoses, unfortunately you can judge them simply by whether they are pliable or not and this is especially true of brake hoses. They may be pliable but still constricted inside when the inner walls deteriorate. That happened on our 1972 Mercedes 280 SEL 4.5 when I couldn't even blow 100 lbs of air through one of the hoses even though it looked and felt okay on the outside.

The fuel pump nearly always needs rebuilding as the diaphragms will either immediately tear with age or start to deteriorate. In a worse case scenario it can pump fuel into the engine! As for brakes, you should not even move an inch without rebuilding. Personally I would have saved the header for last.

Brake hoses and cylinders (all five) rebuilds are first on the list if you're going to try to move it under its own power, then fuel system including pump, tank (which you fixed) and carburetor. It is only after all that that you start it up to see if it runs and I believe all this was stated in one of the first posts after your initial one. At the time time you were anxious (understandably so) to get it running so that you could drive it!

When the time comes to finish, are you going to use a filler primer? That type of primer is relatively thick and will fill minor imperfections.

You're going to need a gasket set anyway and the seals generally come with it. I get my gaskets, whether individual or sets, from Olson's in Washington as their prices are good and I like to support family-owned and run businesses. Although they make many of their gaskets, the sets are probably FelPro or one of the others.

The fuel pump should have been one of the first things rebuilt, along with the carburetor, as the old ones cannot handle modern fuel whether ethanol or not. There is a number stamped on one edge of the pump flange showing which pump it is so that you know whether it belongs to your model or not and so that you can order the proper kit. Many look the same externally but have different innards so you'll probably have to pull it off and clean it a bit in order to see the number.

The vacuum lines from the pump booster actually connect by short rubber hoses (make sure it's for vacuum) to steel lines, one of which connects to the intake manifold and the other runs up to the wiper motor where another line connects it to the motor.

As for the shoulder screw, the purpose is to tighten against a surface (in this case, it's the block) while allowing whatever it is holding to be able to pivot or otherwise move. In this case, the wave washer keeps the distributor from moving too freely when the other bolt is loosened so it's important that the washer is intact.