Mystery holes in Holley 94’s

[Ziggster]

As you may have noticed based on some of my other threads, I’ve been rebuilding one from the carcasses of three. After cleaning and bead blasting what I thought was the premier one, i noticed a hole behind the choke plate linkage. Luckily, the second best did nit have a hole. Upon closer insoection of the third, I noticed it had a series of holes formed to make a slot. Both holes will provide atmospheric pressure to the accelertir pump well (I believe that is whatcitvus called). I’m guessing having two out of three carbs with these holes is no councidence. So does anyone gave an idea why someone would make these holes?

[Ziggster]

Hmmm...Can't upload pics again...

[ford38v8]

If I am understanding your description correctly, the hole(s) you refer to was the second of three versions of float bowl vents. The original location of the vent was an oval vertical slot at the front left side of the air horn. The hole you refer to is at the rear of the accelerator pump, passing through to the float bowl. The third and final location was by means of a tube added at an angle within the air horn itself.

[Ziggster]

Finally...

The “second” carb. Hole is behind where choke link was located.

[Ziggster]

The pic of the third carb will not load...

[1952henry]

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As Alan mentioned, that is a vent. S'posed to be there.

[Ziggster]

Strange. Now works.

The “third” carb with hole.

[1952henry]

Again, credit to Alan. That is an early top with the first version of the vent. I read somewhere that the crank mounted fans wreaked havoc with that vent, therefore the search was on for new location. I think I read it on the interweb, so it must be true.

[Ziggster]

Interesting as I understand that there are something like 17 or 18 versions of Holley 94. I'm positive the holes in my two carbs are not OEM. Whether they were made after the fact or were part of the origin design, what would be the purpose?

Some closer pics...

[Ziggster]

Third one...

[Charlie ny]

Steve,
Hole in photo 2 & 4 IS factory....hole in 1 and 3 I think would be more tucked in
if OEM, looks home drilled.
Charlie ny

[1952henry]

Many versions of the body, different model numbers, different size venturis, vacuum port, or not. Differences in tops would be vent location and car vs truck. I have a few tips with those same holes.

[ford38v8]

Those holes are the correct locations of the factory vent holes, but they do look to have been goobered up by some misinformed soul for who knows what reason. They don't look nice, but shouldn't affect the operation of the carbs.

[Newc]

Hi; I was told the 91-99 with the original front vent was for the crank fan models only. High mount fans required the internal vent.? Newc

[ford38v8]

Originally Posted by Newc

Hi; I was told the 91-99 with the original front vent was for the crank fan models only. High mount fans required the internal vent.? Newc

While the location of the vent was changed twice as it was thought to be affected by air circulation, the timing of those changes was not related to the location of the fan mount.
To further complicate the question today, when carbs were rebuilt back in the day, there was no effort to match original carb bodies and air horns, resulting in an occasional mismatch showing up on the Concourse.

[Ziggster]

Thanks again to everyone. The knowledge out there is just incredible, but more important is that fact that people are willing to share so newbies like me can learn. The "second" carb., the one pictured in posts #4 and 9, does have "Model 59" cast into the bowl section. My "good" carb has no distinguishing marks, but both do have the "94" cast marking, but of course I have mismatched the parts to make a good one. Good to know even concourse quality cars can sometimes muck this aspect up. Lol!

[1952henry]

The " no mark" carb was most likely an over the counter replacement.

[Ziggster]

Just to kinda close the loop, I did find a couple pics of the carbs with the correct vent holes. As @ford38v8 so kindly pointed out in post #13 someone must of "goobreed" them out.

[Ziggster]

The slotted or oval hole.