I am interested in the reasons why tterrace concludes for 1927.
In the reverse picture detail I only see:

1 - 99[.-...]
19 CAL[IFORNIA] ..

So why 1927? Tterrace, please make me wise.

[The plate format shown in the photos in my comment was used only in 1927 and 1928; 1927 was a guess based on what seems like thicker characters in that year. -tterrace]

Note the "K" tread design and monogram (which may be the reason the picture was taken -- retrofit your ride with modern Kent Balloon tires).

I'm going with 1927.

A little hard-used. Top is missing, running board is distorted. This could have been taken in the late 30s or even the 40s.

[The license tag, tires, and fact that the photo is a 5x7 glass negative, point to an earlier time frame. - Dave]

It's a Packard. Around '23. The radiator cap has been swapped out and I don't blame them. This cap is beautiful. If you look at the radiator, the top has a curved slope that was found on the Packards. Above the running board towards the rear, you can find an oval access hole. These items are the same on both vehicles.

I'll say it's a 1923 Packard SportPhaeton.

Placing the model year as 1924 due to the drum headlights but the spare wheel mounting seems to be after-market as it is not recessed into the fender. Four wheel brakes narrows the field but positive as a Packard would be iffy.

The hood ornament is the "winged sea goddess" radiator cap from a late 1920s Hudson:

It's a mid-1920s Packard, not a factory dual-cowl phaeton. The rear windscreen appears to be an add-on accessory. Back then it was quite popular with the higher end automobiles to accessorize the hood ornament with something other than the factory job. Packards at the time came with Motometers.

Maybe around 1925 and might be the Model L.

Packard; note radiator top.

it's a 1928 Cord.

Some model of Packard, maybe 1926 Touring? Should be plenty of experts out there.

All the salient parts match. The Buffalo wire wheels are a conversion—you can see the original holes on the brake drums. The radiator mascot, bumpers, spotlight, and side-mounted spare are contemporary accessories, or cadged from other cars. The rear windscreen may be the same, but with its wings folded in.

Edit I forgot to attach this photo earlier-- the radiator-shell shape, matching headlight bezels, the hood louvers and latch, windshield frame, belt moulding, long radiator neck, and access port for greasing the rear spring shackle, all point to the Packard. Their Model Series didn't line up exactly with the calendar, so the year model is not completely unambiguous.

The hood ornament looks like it belongs on a Rolls Royce.

According to Google "Images for hood ornaments guide", second picture in, it could be an Auburn between the years 1928 to 1931. That's based on the hood ornament, but photos of the actual car (compared to the Shorpy picture) don't really match.

The hood ornament is the only thing to give you a hint.

I think that this high-style cruiser is a 1922-1923 Packard Model 126 Sport Phaeton with custom body by Pullman Co.

I am fairly certain that this is a Packard of about 1930/31.

The 'Glass Headrest' is in fact a windscreen for the rear passengers. It has fold-out 'wings' to deflect the rush of air, similar to the wings on the front windscreen. With the roof erected, it also provides a separation for the rear passengers from the lowly chauffeur up front.

It appears to be a 1924 Packard, but the hood ornament looks like it's from a 1928 Hudson. So they lost the Packard's rad cap and replaced it with the Hudson's?

Dual cowl phaeton/ oops i'll change that to a similar vintage Hudson; didn't know they had their own "flying lady."

I can't ID the car, but I can the big house across Jefferson Square Park at the upper left: it's the Fortmann Mansion at 1007 Gough, which in its decrepit state in 1958 portrayed the "McKittrick Hotel" in Alfred Hitchcock's Vertigo. Then a year later it was torn down. Behind the trees at the upper right, St. Paulus' German Evangelical Lutheran Church, built in 1893 at the corner of Gough and Eddy, also made a brief appearance in the film. It was destroyed by fire in 1995.

Packard. Not sure what year, but guessing late teens or so.