What carbs do I have? Filter options?

[Tremelune]

I recently picked up a 1970 911T. It has a set of Weber carbs and a sticker in the engine bay that says "PMO conversion, Santa Monica" from 1977.

I've read that PMO carbs were still labeled Weber during the 70s...How do I know what I'm working with, here?



The plenum on the car has some hilariously-repaired damage. In the interest of not buying another one for a grand before my first tank of gas is through, can I just pick up a set of $250 PMO filters and rain hats without reducing performance? Are there any fitment concerns, or are they all pretty much the same for all years and venturies?

[boxer246]

I may be wrong but what I think you have here is a set of Spanish, not original Italian, Webers. Some may have been made in the US also? Seems like I read that somewhere.
I don’t know that makes them necessarily any worse, less desirable or less functional than the Italian originals, but that is a debate for more knowledgeable people such as Paul (1QuickS on this forum).
Yes the rain hats will work fine for these carbs. They’re not specific to different Venturi sizes. Don’t know if the 46IDA’s take a different rain hat…but you’ve got 40’s so that’s irrelevant anyway.

[1QuickS]

Those were made by the Carter Carburetor Company in Sanford, North Carolina starting in 1979 and continuing through the early 1990s. Quality control was poor and many had issues that landed them in the scrap pile. I have serviced many sets of these but they all came from running engines so they were good units. I do find minor machining errors in these, the most typical being the depth of the emulsion well counterbores are of varying heights which can be corrected. Emulsion tube height and fuel level in the float bowl affect when the main circuit is activated so it is good to have the E-tubes and fuel levels at the specified heights.

The Italian triple throat Webers will have "Made in Italy" on the side of the carb. Those made in the USA like these will just have a big "W" and "Weber". I have seen a very small number of these Webers that have "Weber" and "Italy" which I believe to have been of Spanish origin.

Richard Parr (Porsche Mail Order became PMO after Porsche objected to the use of their name in Richard's business name) starting selling Weber conversion kits using the USA Webers and continued until he developed his own triple throat carbs.

The typical K&N filters with water shields will fit fine in your engine bay, especially with the standard height (short) intake manifolds you have. You will have increased engine noise from the intakes which I enjoy but can be tiresome for passengers, especially on a long trip.

[buster73]

Some PMO kits also were emission legal, even fulfilling CA emission requirements in the 70's.
Attached the sticker from my 73 engine bay. Of course not an issue anymore for smog-exempt classic cars.

[Tremelune]

I feel like I know less now...here's that sticker in my engine bay:

[Tremelune]

If I'm distilling this correctly, it seems like Richard Parr did a Weber carb conversion to my car, and his business happened to be called PMO at the time, but that these carbs on my car are not the "PMO carbs" people are referring to, and are instead standard US-made D-144 Webers.

?

D-144 seems to mean nothing, but that's fine...

[buster73]

Originally Posted by Tremelune

If I'm distilling this correctly, it seems like Richard Parr did a Weber carb conversion to my car, and his business happened to be called PMO at the time, but that these carbs on my car are not the "PMO carbs" people are referring to, and are instead standard US-made D-144 Webers.

?

D-144 seems to mean nothing, but that's fine...

As Paul explained PMO started using genuine Weber carbs. Later they expanded in designing and manufacturing their own PMO brand carb line, improving and refining the Weber design and eliminating some of the weak spots.

[buster73]

E.O. # D-144 stands for the Executive Order from the CA air resources board. You can find more details in this forum.