Almost assuredly some previous owner took off the mechanical fuel pump down by the right-hand-side of the engine (there must be a blanking plate over where it would be actuated by the camshaft), and installed the aftermarket electric fuel pump which you have shown in your pictures. As has been said already, in many cases people left the original fuel pump and only used an electric fuel pump as a "priming" pump, also useful for situations with vapor lock.

You have a few choices:

1) Keep the setup you have and rebuild or otherwise refurbish the Stewart-Warner (IIRC) pump you have. That's not a stock Packard item, it is aftermarket, that's all I know.

2) Get rid of the electric pump, and as some have suggested, put a mechanical fuel pump in - I believe you can get a refurbished mechanical fuel pump from Kanter Auto (www.kanter.com) or Max Merrit (packardparts.com), or many others. Best to call them.

3) Install a mechanical fuel pump and an electric fuel pump to act as a priming pump. There are a few pumps people have used, there are other threads to that effect here on this website, do a search for electric fuel pump.

4) You can replace the electric fuel pump you have with a new one, again do a search for electric fuel pump on this website.

You are right that Hankook H724's have been discontinued, there might be some available in warehouses.

The Kinergy H735 has the option of either raised white lettering or blackwall. Hankook from what I can tell, does not have any other whitewall tires available in current production.

The following tire is available from America's Tire in a 235/75 R15 size with whitewall. Maybe there are others.

Nexen N Priz AH5, 235/75 R15 Thin Whitewall

Would it make sense to put the Volkswagen and Harley switch (along with the aftermarket equivalent) in the X-Ref? I assume the Harley Switch would work for the 1951-54's as well with the TreadlevaC?

I don't know what size they are, but it's rather simple to figure out, just take the one off the output from the fuel pump, which should be a short hard line, and take it to NAPA.

For reference, the Factory Parts List to the left has the parts plates, which can also be found as a PDF in the Factor Parts Manual, 1948-54:

Parts Plate, 1948-1954

The fuel system is illustrated as plate 103A, and the primary fuel line itself is Group # 9.400. Group # is the weird Packard way of assigning a part grouy for a part, then you look up the actual part # for your model and year in the Parts list.

So if you look up group 9.400 in the Factory Parts list, you get
Factor Parts List, Group# 9.400

you get #446359 for chassis #2626/5426

I haven't used them (yet), but Ross Miller recently recommended them to me.

That's not necessary. Other folks can weigh in here better than me, but you definitely don't need an arbor press. Remember these seals were/are replaced in-the-car regularly, even (and especially) "back in the day". You basically just need to "roll it" with a socket or something before you install the crank.

Here's a video, I did something very similar to this:

Installing a Rope Rear Main Seal.

I am sure someone else on this forum has even better instructions/suggestions than this.

For my Cavalier, which uses 8.00-15, I have 235/75 R15 Hankook H724 thin whitewalls. Those work well. The Coker Tire chart

Coker Tire Cross Reference Chart

says 8.00-15 should be 235/75 R15 and 7.60-15 should be 225/75 R15. Looks like those tires are available as both 225/75/R15 and 235/75/R15
America's Tire, Hankook H724

PM sent

As mentioned, some folks have these either in place of or in addition to the mechanical fuel pump. One common usage is to have the electric fuel pump in-line with the mechanical fuel pump, operated by a switch somewhere on or under the dashboard, turn it on for a few seconds before starting up, but leave it off in normal operation. This keeps one from having to run the starter a while to get fuel up into the carburetor after a long time sitting as is a common use-case with vintage cars. Some folks don't have this problem, seems to have a lot to do with the fuel available in the area (esp. as regards the quantity of ethanol) and the conditions in which the car "lives", e.g. temperature-controlled garage or not. Folks in hot climates also use it to prevent vapor lock, especially at hot startup, using a similar strategy. Basic point - it's not verboten to have one on your Cavalier, many do for legitimate reasons - vintage cars are not operated as frequently as "daily drivers", and because of the different characteristics of modern fuel, vapor lock can be more of a problem than when the car was built, as was detailed in a series of recent articles in the Packard Cormorant club magazine. There is a heat shield that is provided between the mechanical fuel pump and the engine, which has sometimes been removed sometime in the past by a mechanic who was too bothered to put it back on (these are available from various Packard vendors as I understand it), and there are insulated fasteners used to mount the fuel pump to the engine, both of which are there to help prevent vapor-lock. There are threads in this forum on how to properly select and install an electric fuel pump without having to remove the mechanical fuel pump.

Thank you for the detailed description of the pinion seal replacement. Where I ran into trouble was after removing the large U-shaped clips, the bearing caps would not budge without applying some force to push them put of the joint. I guess people use a ball-joint puller for that, I was using a C-Clamp with a large socket to push on the opposite side of the joint. That was working but the force required was at the outer limits of the C-Clamp, finally I thought better of it and just pushed everything back and put the clips back on.

I was having trouble similar to this thread:

Rear U-Joint disassembly

As far as tires, I have been very happy with Hankook H724 thin whitewalls, which will set you back maybe $500 for a set of 4, assuming you can still get them, I purchased some last year without any trouble.