My best guess is the 323 would fit, but if you could share pictures of your gasket and better yet, measurements, that'd help.

You could also try e-mailing Silca with pictures of your chuck and gasket. I'm sure they can either tell you definitively, or would be interested in figuring out the answer to update their product description.

The rubber "gasket is 13mm OD and about 9mm deep(best guess) Of course it has the standard hole for a Presta vavle
https://cimg2.ibsrv.net/gimg/bikefor...b723cf5d2e.jpg
https://cimg4.ibsrv.net/gimg/bikefor...9265a50cab.jpg

Love these pumps - usually can be had at church sales for a buck or two.

The blue one is my daily driver. The others need a "vaseline job" and hose work.

https://live.staticflickr.com/4499/3...2f723533_k.jpg

I tried mine again today, the older one. I discovered that I was not pushing it on the valve far enough. Once I had a good engagement, I was able to pump it up to 125 with the gauge indicating 120. The check valve isn't working well so I will have to check it out.
I was surprised how easily it pumped to that pressure

@ Thinktubes If you find another one for a couple of bucks, buy it and lets talk!

That sounds like what I remember the 323 to be. If I remember my numbers correctly, the ID of the barrel used with the 242 gasket is around 15mm. There's one other available gasket, 252, meant for the disc wheel chuck (some refer to the shape as a 'crack pipe'), but that gasket is much thinner and your chuck clearly isn't that shape. I'll try to measure my pumps this weekend to confirm dimensions, but I'll be surprised if your chuck doesn't take the 323.

The barrel of your chuck appears to have threads on both ends. I'm curious - are both ends identical? Some related chucks are reversible - you can flip the barrel to go between presta and Schrader, with the cap having threads letting it screw on a Schrader valve. The hose barb actually swivels within its cap, sealed by an O-ring. Mine came without lubrication for that O-ring and it I had it for years before realizing the barb and cap weren't a single solid piece!

[MENTION=524607]luns[/MENTION] - The barrel does have threads at both ends.
https://live.staticflickr.com/65535/...1dfde837_b.jpgP1040805 on Flickr

The gasket is 8mm long in its present form I suspect it was a bit longer new, before being compressed by the cap. hard to get good pictures lately, may need a new cameral.
https://live.staticflickr.com/65535/...7d7bd448_b.jpgP1040801 on Flickr
https://live.staticflickr.com/65535/...88125da0_b.jpgP1040804 on Flickr
https://live.staticflickr.com/65535/...62a0703d_b.jpgP1040803 on Flickr

Here is the interesting part, the opposite end of the barrel. The barrel is not a straight through bore but has a partition with a small hole in the center with this gasket on the other side.
https://live.staticflickr.com/65535/...83730d61_b.jpgP1040806 on Flickr

Know idea how a shreader valve is accomidated.

This is the end piece on the hose
https://live.staticflickr.com/65535/...f7e9af51_b.jpgP1040811 on Flickr

Thanks for the pictures! That gasket does look like a 323. The other end of the barrel is the same as my reversible chuck - the brass bit in the centre is a depressor to open a Schrader valve for inflation. Lucky you, it appears you already have a spare gasket! If I'm not mistaken, the gasket around the depressor is another 323 identical to the Presta side, so you should be able to just swap the two to get a fresh(er) Presta seal. The worn presta sealing surface won't matter on the Schrader side. The existing Schrader side gasket hopefully has an unworn Presta surface, although the rubber is probably somewhat hardened by now and might not seal as well as a new part, but it should still be better than the equally old worn part.

I haven't used the current replacement 323, but did recently replace the 242 on my '03 Pista. The new red material works very well, and was day and night compared to the worn and hardened old black rubber.

If the cap doesn't have threads on its opening, then it won't work for Schrader, but from your photos, I'm starting to wonder if they might actually be there and just hidden by grime. I suppose it wouldn't hurt to just try and see if the cap will thread onto a Schrader valve. It may be though that your chuck, although it shares its barrel with the reversible chuck, was only meant for Presta. Some versions of the reversible chuck have a much thicker snout on the cap to provide more meat for threads, but I seem to remember an old chuck I used to have still had a thin flat face.

The cap on the hose end looks much like the part on my reversible chuck. The seam between my barb and the cap fit so precisely the seam was literally invisible. If you try twisting the cap relative to the hose, does it move? It may take a fairly firm twist, and it may feel like the barb actually twisting in the hose instead (this is what I thought I was originally doing using the old chuck on Schrader), but you can take a sharpie and draw a radial line on the inside face of the cap to see whether that's actually the case or not.

This insert appears identical to the one in my early '00s Super-Pista handle.

https://www.amazon.com/Z-Threaded-In...dp/B07V8ZS86N/

Unit cost seems very reasonable to me, but I'll be forever looking for things to do with 24 spares.

Not that I would actually do it, but I'm imagining decal A below (from Cyclomondo):
https://cimg1.ibsrv.net/gimg/bikefor...2e4cf1d776.jpg

Quite possibly: the size and threading are correct, at least the one I can compare to at home has that rod but it's a standard pista with the oval plastic handle.
The oval plastic has a brass threaded insert and it's molded in place.
Personally I would look for a screw-in insert that was also brass (or steel) because these cast zinc jobs do not inspire confidence: that's the (soft) metal you find used for very soft substrates like MDF. Seen too many things like that crumble (looking at you, IKEA).
I would want stronger metal cause I'd use a harder wood for replacement handles. YMMV of course!

Why I oughta 😉
You motivated me to dress-up my 2x8 drop with a piece of scrap Australian Blackwood as a veneer to the old fir base.
Leftover scrap from an acoustic guitar build that went awry...

https://cimg5.ibsrv.net/gimg/bikefor...adbd2c931.jpeg

Wow, That is mo' pretty than I go for: I just use plywood! But now I'll have to snap some pix (...sigh...)

https://cimg3.ibsrv.net/gimg/bikefor...71b8a654f2.jpg
This is the Silca pump mentioned by Juvela. I asked Silca for dating and they told me around 1960; to me i think it is older than that with a brass tube beautiful Cast Aluminum foot rest and the hose is special stainless steel webbing i believe. Like motorcycle heavy duty hydraulic brake hose.

As I promised (or threatened?) I took a pic of two of the Silcas I have at home with wooden "extra bases" I made and added. They are both black Super Pistas but the one in foreground with the typical base has the "capsule" shape I made most often. I added this to Regular as well as Super Pista pump bases. The one in background has the later "triangle base' so I tried something different shape-wise, but didn't want to try to follow the base outline cause I wanted the footprint to be closer to that of the capsules. Tho mostly I use scrap plywood this "capsule example" happens to be a solid plank; the other is plywood with an exotic wood veneer, I think it's teak (or something "close" they now substitute since real teak is endangered). Maybe I'll snap pix of the others at "the shop" but they are just variations on the capsule, only with different veneers on the plywood or perhaps a nicer close-grain solid pine plank.
https://cimg4.ibsrv.net/gimg/bikefor...9b71486483.jpg

Interesting to add a base. I would not drill a hole in mine.
In addition, mine is slightly bent, and trying to bend it back may brake it. Looking at the bottom, it looks like it should with most of the wear on the non gauge side.
My suspicion is that it was used on grass, gravel, or soft dirt that caused the bend over time.
https://live.staticflickr.com/65535/...dd750de7_b.jpgP1040756 on Flickr

[QUOTE=luns;21964588]Not that I would actually do it, but I'm imagining decal A below (from Cyclomondo):
https://cimg1.ibsrv.net/gimg/bikefor...2e4cf1d776.jpg[/QOTE]
Hmmmmmm.

I took some snaps of one (Standard not Super) that I made a replacement wooden (white oak in this case) handle with an "experimental shape" to replace the lousy black plastic "oval". It was a choice as much dictated by style as by ergonomics, but I can say it is far more comfortable than the "oval". And the base is my go-to "capsule" shape, this time plywood with an oak veneer. This handle has a steel threaded insert (M10) I filed down a little: worked out fine, and not expensive when you buy 25 of them!

https://cimg7.ibsrv.net/gimg/bikefor...f55bf30dda.jpg
Have to figure out some elegant "hose-caddy", the rubber band ain't doin' it!
https://cimg9.ibsrv.net/gimg/bikefor...e2d4e489e0.jpg
the steel threaded insert

I rarely use mine. I still have not found the correct gasket for the head. It goes on and I am able to pump a tire up to the desired pressure, but the valve has to be forced deep in to the head.
The oval handle is not comfortable unless you use one hand!
What I find a bit puzzling is the brass piece with the gauge and out put of the hose. It looks like it was meant to be used with the left foot. I have been using the right one.

This pump is more of a show piece for me than a commonly used pump. My compressor is used to take the tire up to its max pressure then finished off with the white pump.
I am reluctant to drill holes in the base or replace the handle given the challenge of the head. It will remain fully original, otherwise.

Is this the gasket for the head you need?

​​​​
Otherwise I just replaced my hose and head with this. It's a bit sacrilegious but I use the pump plenty.

My pump for reference.
 

https://cimg3.ibsrv.net/gimg/bikefor...30563ad2ba.jpg
I've had a couple of classic Silca's one was black exactly like the OP'rs, but lost it while supporting a Leadville 100 team as a mechanic somewhere.

This one had a bad leather washer which I replaced and a bad hose, which I replaced with this dual head Sunlite thing which is my favorite chuck head. Way more functional but these pumps are better for 28c tires and smaller to dial in the exact PSI needed.

I never owned any with that "more vintage" base, but the slightly newer Standard base (which I have multiples of) has one hole already factory drilled, and I have no qualms about making mods including drilling 2 more holes in those bases. Likewise I would not hesitate to use non-Silca replacement hose (done that many times) including one with another Brand's hose-head (also have done it).

The example I just posted above with the oak handle had a warped base and when I screwed it to this wooden base it flattened out without cracking (maybe I just got lucky).

You can sometimes re-orient the gage so it's right-side-up in the position you use the pump (I like my gages on the left, but sometimes they are upside down in that case), and sometimes that won't work. No idea why I have examples of same pumps with "original, factory" gages in both orientations: it's not like they sold them in "left-hand or right-hand" versions. Apparently Silca didn't think it made a difference, and when I can't flip the gage and still have it seal I just adapt to reading it upside down.

Slight drift here. How do you determine what model you have and what the differences are between them?

I bought this off of Craigslist several years ago. I use it , but my Park pump gets the most use.

https://cimg8.ibsrv.net/gimg/bikefor...7e280f3404.jpg

That one is a Super Pista due to longer (taller) body (which you have to compare with the Standard to see) plus the larger wooden handle, top cap with built-in hose "caddy", this also is a more modern Super Pista due to both the Trangular base AND the gage "shroud" plus the larger graphics on the barrel. Earlier Supers came with the same base as the Standard Pista (and was extra-unstable due to that) plus these wooden handles were both drilled thru with curved washers and a top Nylock nut or with a threaded insert (as yours has).

And my slight side-bar: I think every OEM wooden handle I have seen has been Beech, and even tho I think I'm good at wood species ID I could be wrong. Did not think of Beech as a common lumber in Italy, (EDIT: wrong! Beech is a common wood in Italy, especially for furniture. Interwebs sez so, BUT now revising my opinion to allow it may be Boxwood) so any of you woodworkers out there who want to go down a tangent.... ;)

I

I don't know. Just ordered one. I sent measurements to Silca and they tole me I needed the 272 which is way too big. I can still upgrade my other chuck with it.

.
...I know that the original Silca Presta chuck is a wonderful thing, but I finally got tired of dicking around with it. Stuck one of these on it. Works fine, and I put the old chuck in a parts drawer labeled "pump".

https://cimg2.ibsrv.net/gimg/bikefor...633f47cb4e.jpg
Apparently Tpeak has stopped making and selling these, and now sells something similar (but not identical) in a silver metal version. I can't vouch for those, because I've never used one.