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Discussion Starter #1
Hi all.

67 SS 396. I've noticed when taking on-and-off my air cleaner and base that when I put on the base, it actually hits my Holley carb and causes some gas to squirt out of the jets. I can see that it's visibly touching when the air cleaner is bolted down.





My mechanic thinks that I might have the wrong drop base (for a Quadrajet, not a Holley). I notice that it's the tube connected to the valve cover vent that it's hitting the Carb.

I really don't want to cut this vent tube off... but it's clearly interfering with the carb. It's already dented in (probably the previous owner trying to remedy this situation... so maybe cutting it off isn't a big deal).

I bought an Edelbrock valve cover breather so that I can eliminate the tube connecting to the air cleaner. That vent tube won't be serving any purpose anymore.

Do I have the right drop base? A flat base doesn't seem to clear the hood.

Thanks!
 

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There are air cleaner spacers in different sizes you can buy to raise the base how ever much you need for clearance.
 

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That is the fresh air tube fitting, it connects to one of the valve covers to allow filtered air into the engine for the PCV system to process. Some times, the base can be modified such as you have attempted to do with the dimple, and some times, the base itself can be rotated on the carb just enough to clear things, but, if there is clearance, a simple spacer, as suggested above, is the answer, IF the base is the right one for the carb.


Also, from your picture above, it appears you need to set up a degrees stop on the vacuum advance, then plug it into the full manifold vacuum port with the black cap on it, just below the choke.



More info on how to do it right, [email protected] Ask for the degrees stop package, it is totally free.
 

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Fel Pro Perfomance offers an air cleaner gaskets with adhesive on one side, part number 2104. You might be able to stack a couple and gain the clearance you need.

Steve R
 

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'66 Aztec Bronze
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Welcome to the club of a modified breather tube on a drop base air cleaner. It seems like anytime I see a drop base for sale at a swap meet; the tube is mangled - prolly to address the same problem. Evidently that doesn't work so the base goes out for sale.
 

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Hi all.

67 SS 396. I've noticed when taking on-and-off my air cleaner and base that when I put on the base, it actually hits my Holley carb and causes some gas to squirt out of the jets. I can see that it's visibly touching when the air cleaner is bolted down.

My mechanic thinks that I might have the wrong drop base (for a Quadrajet, not a Holley).
Do I have the right drop base? A flat base doesn't seem to clear the hood.

Thanks!
Get a new mechanic... He doesn't know what he is talking about... ;)

Honestly, you have the wrong carb. The base looks correct.

Your carb is a "double pumper", and its hitting the secondary accelerator pump. ALL factory installed Holley carbs are "single pumper" with the vacuum secondary pod on the side (not including Z28 cross rams and L88s, that were factory racecars).


Also, while it should still fit, the factory Holley for that intake will have a single inlet fuel line. Your carb is an aftermarket Holley double pumper with the dual feed fuel line and a cable-operated choke (you can see the factory "divorced choke" on the intake below the cable choke.
 

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This^^^^....the factory drop base was never made for fitting the Double Pumper carbs....that's why it hits.

If you're not going to use any means of spacing it up enough to clear, or If your not going to use the fresh air tube as GM designed it, cut it off at the base and cap the hole by welding or epoxy glue a cover where the tube was.
 

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1970 SS 396 25-C, 1966 SS R-R
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I have removed the vent tube and sealed the hole in order to use it on a double pumper. Then I use the AC brand push in breather in the valve cover. The tube in the base is spot welded in place. Remove it carefully so it can be reinstalled if needed.
 

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our oriely autoparts has a small perf section and used to have a carb spacer kit on the wall. they come as small as 1/2 inch thick. jim
 

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Maybe just go buy a nice drop base 3 inch air cleaner set up that has the clearances you need for the double pumper. If you raise it too high you may run into hood clearance issues.
 

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Discussion Starter #11
Thank you everyone for the advice and guidance! I'm learning so much about this car and am really enjoying taking it apart (slowly) to address the little issues. Thanks for your patience!

I bought this spacer kit and will try out the smallest 1/2" spacer first when it arrives.

https://www.amazon.com/gp/product/B004AJ3306/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

I'll probably just cap the breather tube since I don't want to mess with cutting/welding (even though somebody before me already "dimpled" it).

Thanks!
 

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If you even decide to reuse the tube on air cleaner make sure you undimple as best you can that thing needs to flow. Hard to tell from photo how much it is squished.
 

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Discussion Starter #13
If you even decide to reuse the tube on air cleaner make sure you undimple as best you can that thing needs to flow. Hard to tell from photo how much it is squished.
I doubt I could effectively undimple this breather well - it's pretty well dimpled in. I bought a valve cover breather cap, so I don't think that I need really need this tube... right?
 

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I doubt I could effectively undimple this breather well - it's pretty well dimpled in. I bought a valve cover breather cap, so I don't think that I need really need this tube... right?
Correct no need for it if you are running the breather. It is only if you were to ever reuse it in its stock form. You could probably get most of it back open with an socket extension and hammer. You could also just find another bottom if it were an issue. If the spacer works then you could put another one with a tube on it back. But as I said with the breather that is now your new fresh air source and vent.
 

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perfect, i had my kid the fabricator cut off the bend and weld in a flat there so it clears the 850 DP fwiw.
 

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66 El Camino 57 Chevy pickup 2004 Tahoe
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Chevy didn't sell cars with double pumpers (except maybe some L-88s and ZL-1s) so the air filter housing is not designed to clear the rear pump. Been like this since the beginning, which is the reason why so many cars are butchered up with different air filters. I personally don't know of a quality aftermarket air filter base that will fit correctly on a DP. Also add in problems fitting with an HEI and it's no fun getting it together to look right and function correctly.

That Amazon link to the airfilter spacers is the best deal I've seen for solving this problem.
 

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.

That Amazon link to the airfilter spacers is the best deal I've seen for solving this problem.
Well, a little bit of fabrication is all that is needed. Helps to have a tig machine.
 
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