Zenith Restoration/Rebuild Question...

[detroit]

So, awhile back I bought a 914/6 motor with the intent of putting it into my 914 as a replacement for its factory 1.8. It came with two sets of Zeniths. I'm rebuilding/restoring both sets of carbs (along with a set of IDTPs). One of the three sets I'm going to retain, and sell with the motor, which has itself been replaced with a 3.0SC plant. The other two I'm going to shift on their own. Of the two sets of Zeniths, one came with the auxiliary enrichment set up; one did not. The question is how were the enrichment ports originally plugged in cars not equipped with the auxiliary circuit? As can be seen in the pictures they are filled with an epoxy of some sort. Was this OEM? I'll leave them as is if that's the case. Otherwise I'll probably machine out the epoxy in lieu of a more elegant solution.
Many thanks...

[detroit]

Since we're on the subject, here are a few more pics...
Everything going into these carbs is either going to be new or refurbished. I've new shafts and blades and of course seals, gaskets, etc. All the steel bits have been replated.
And, I've re-Alodined the castings. Curiously, they came out a different color to the Webers despite being immersed for the same time. I'm not sure that either is truly correct from a concourse standpoint, but I couldn't find anyone to Alodine them for me. I had to do it myself, and these chemicals are what's available.

[buster73]

Nice work - looking good.
Not sure if I ever came across a 40 TIN without the enrichment circuit ? Guess the epoxy plugs are fine, but I opted to cut a thread for the center opening, so I can plug all openings with bolts and washers. Easily reversible if needed.

[john walker's workshop]

You have webers and you're going to use zeniths on a 3.0?

[911 SLANT]

If you can go with Weber or PMO. I switched from Zenith to PMO and what a difference with adjustment and performance. Good luck!

[crater64]

Originally Posted by john walker's workshop

You have webers and you're going to use zeniths on a 3.0?

I wanted to keep my Zeniths on my 2.4SS build but the builder - and most everyone I talked to IRL or online - persuaded me to switch to Webers. I was able to sell the Zeniths to offset some costs and also used my stock crank and rods. Gotta contain costs somewhere!

[911 SLANT]

+1 on selling the Zenith carbs.

[detroit]

Thanks guys, but to be clear, I am not using Zeniths on the 3.0 I'm rebuilding.
I have a set of Weber IDA's for that. The two sets of Zeniths and the IDTP's are extra carbs that I have.
And, Buster, the 911 tech spec manual for '69-'71 suggests that '70/'71 US models received Zeniths with the enrichment circuit while RoW 911's got Zeniths without it.
I am certainly no expert on the subject, hence the original post. I agree that a threaded plug or cover plate would be a more elegant (easily reversible) solution, but one of these sets came with the epoxy. I have to admit that it was really well done. Almost as though the epoxy was added to the casting prior to machining the surfaces...
I can machine it out, but if this is how they came from Zenith, I'll leave as is.

[buster73]

I did a direct swap from Webers to Zenith on my 2,4 and was quite happy with the result.

Weber-Zenith swap for 2.4T

For my 3.0 project I still opted for Weber IDA`s as they are easy to adjust for larger displacement engines (e.g. venturi size...).