This could be a bit of a think tank on the non sidedraught two barrel line of Weber series of carbs suitable for A series use.
As I am offering this thread up as a discussion forum, please hop right in with your thoughts.

Here's my offering.

The picture below is of a Weber 32 DIR-21 carb, used as an OEM fitment on a Nissan affiliate car company brand, .... Renault.
There were a number of versions, some with fittings or features for smog stuff & others that were configured for auto trans models.
In this particular group we have 32 DIR-21, 24, 29, & 49A
This one's a 32 DIR-21 & looks like the base model carb.

I think that it has some features to offer that might be attractive to some Datsun owners.
It is, as can be seen, a DGV series lookalike, but with the following plus & minus points. You be the judge of which is which.

32/32 throttle sizes. The 32/36 is designed for a 2 litre engine which may well be just too much carb in some applications.
This one was used on high performance 1200cc engines, & others up to 1600cc. This makes it well suited to hot A12's up to warmed over A15's

It has a manual choke.
Aussie small Datsuns have a factory installed choke cable.

The throttle shaft rotates clockwise [in this view] which means that the throttle arm is pulled.
Our Datsuns come with a throttle cable that pulls.

It does not have an idle cut off solenoid function in this version of this carb.

The fuel inlet fitting faces directly ahead.

It fits the standard Weber carb adapter. [It's sitting on one in the pictures]



































In the second picture we can see more of the important bits.

The throttle arm is mounted upwards & is pulled to the right. In the original application the carb was on the right side of the engine, but in a Datsun it will be on the left.
This will give us much better access to the idle mixture screw & the idle speed screw as these are now on the side nearest the fender. The down side is that the choke cable originally entered the cast-in lug just below the top gasket & ran across to the choke lever on the right of the picture. The choke lever moves towards the carb to activate the choke function. An inconvenience, but this can be overcome without too much difficulty. [More on this later]

This positioning also places the choke pull-off vacuum chamber & the accelerator pump on the 'accessable' side of the carb in the event that they need servicing. This can now be done 'in situ' much more easily, as can adjustments to the idle mixture & idle speed screws as mentioned earlier.

Nice pictures... The DIR as far as I know is a progresive. So it would be a progresive 32/32....... interesting....
More efficient and responsive w/o boggin down .... Never seen one in a car, but I read about the kits..it is used extensively....would be nice to test it on a healthy Datsun.....


.....


.....

Yes, it is a progressive carb, & like other progressive Webers in this group, it's a mechanicly linked progressive carb instead of having the opening of the second throat controlled by a vacuum diaphram as in many Datsun OEM carbs. That system is probably better for economy, while the Weber system will lean more towards performance as the second throat will open when the throttle is floored, regardless of manifold vacuum.

Note the water fittings on the base of the carb in your pictures. This is simply a straight through passage that heats the plate nearest the idle port. It's good for situations where the outside temp is very low & can be retained if desired, but I removed the one from under my carb.

Specificly, what model is the carb in your pictures?

In this view, we can see the usual Weber filter under the fuel inlet fitting & of some minor note is the ported vacuum fitting, which is now located away from the engine. This involves an extra 30 seconds of thinking on how best to route & secure the hose. Again, not an insurmountable problem.

The pictures are from a Weber 32 DIR intended for a Renault 1100. In E/Bay, there is a guy ALFA17 that sells remanufactured Webers. I got the pix from there, there is pictures of several other Webers used apparently in Europe's vast array of cars. Europe has a lot of smaller vehicles, so in that respect, there is a lot to learn about application to smaller vehicles.

I can not get much information about the DIR, the DCNF , the DFV....all the information, at least on this side of the Pacific/Atlantic is mainly about DGV, DCOE and DGAS. I guess it would be extremely usefull to get a Weber book from the European market. Different markets get directed towards different products, and we all live within that micro cosmos. Some guy from Thailand ( I think it was Thailand) inquired about using a DCNF. Everyone I asked about it here just looked at the roof as I was talking about it...... unknown!

About the DIR , I like the fact it is progressive 32/32...that makes it more efficient allowing the acceleration curve to raise in a rationalized manner.

I will investigate....Italy must be a playground for all this exotic Webers.....with all those Fiat cars with small engines but tuned up in a sport manner.

The DIR and other Webers are used so extensively, that the price is lower than the DGV's. So at least in the downdraft market, there is a pletora of Webers to go after . A twin DIR 32 / 32 would be nice.