General Category > Quadrajet Carb Talk and Tips

Bigger holes in Main body and Air Horn than First Recipe recommendation.

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Albert:
Hi All.
I hope I posted this in the correct place.
I bought Cliff's service kit. His advice, and reading on the forum here has been a God-send!
I have measured all hole sizes in the body and air horn of my current (and first) attempt to restore a this Quadrajet which will go on to a stock standard AMC 304 V8.

Do I need to reduce some holes sizes to suit the 304? The holes in the castings, are larger than what Cliffs First Recipe recommends.

Particularly: Idle channel hole, Upper Idle Air bleed, Accelerator Pump discharge holes, Secondary POE Well restriction, and should I reduce the Secondary Air Flap Opening Distance.

I have highlighted these items in red on the document that I will try to attach below, and a couple of photos of where I am at for now.
First column next to descriptor is my Carby, to the Right is Cliffs recommended First recipe for comparison.

Would it be OK to pop it onto the engine and try run & tune it or will these specs just not work?
I look forward to hearing your thoughts.
Many thanks.

Kenth:
You may open the idle channels to .046".
The upper idle air bleeds, .069 are located in the float bowl (not in the air horn) and is on par with Cliff´s rcommendation.
The accelerator pump discharge jets, .026" are located further in thru the outer .060" siphon hole.
The .040" secondary POE well restriction is fine.
The secondary POE discharge jets, .030", are located further in thru the .053" holes. Needs to be opened.
Doesn´t hurt to increase the secondary air valves opening angle.
If you are using an electric choke element and plug the hot air channel, you may want to add some idle bypass air in the throttle plate, .070"-.080" for each bore will do.

HTH

Albert:
Thanks for your quick Reply Kenth!

I had another look, and re-read, and I think I got the correct locations as you describe.
I attach some images of Pin Gauges / drills popped into the locations.

I will appreciate confirmation that I have correctly identified them all, please.

I do not want to drill anything until I am absolutely sure I have identified the correct items, and that they NEED to be drilled for the engine to run correctly.


* Idle Channel (- Are these also Called Down Channels?) Do I need to open these up, or is it a might need?
Should I try run the engine first, then see if it needs opening?
* Upper Idle Air Bleed in Main Body. They are at .069"
* Accelerator Pump Discharge Jets are at .026"
* Secondary POE Well restriction is actually at .039" - not .040" - will that matter?
* Secondary POE discharge jets are at.030" - is this a need to enlarge to .052"? Bearing in mind its only a 304 engine this is going to sit on.
* I'll leave air flap distance as is for now, and see how it goes when I run the engine.
* If I find I need more Idle Bypass Air, where do I drill the holes, and should they be in the primary throttle plates? (I am using electric choke).
Many questions I know!

Below are my Images to help make sure I have got things right before I start to make "permanent" changes to my Carby.

I look forward to your advice  :)

[/list]

Albert:
Hi All.

Thanks again for your initial answer Kenth.

I have confidence in my ability - just not quite there in my knowledge!!  :-[
That's why I have popped my question on this forum.
But man - have I learnt a lot in the last month or two!
I am so grateful for everyone that has posted questions, and answers on the various threads before I joined, and that has allowed me to confirm and learn so much before I jumped in to my first QJet restoration. My second will follow in a few months time.

Would it be possible please for confirmation that I have correctly identified the holes, and answers to my current questions, before I start to alter / enlarge any hole sizes?
Images to illustrate my questions are posted earlier in this thread.

I look forward to hearing from you.
Many thanks.
Albert  :-\

lightning boy:
Albert, as far as the bypass air. The milled slots in front of the primary bores are where the bypass air goes. Look Through the main body from the top and you can see the holes that correspond to where you need to drill the base. Don't drill the plates. One channel is straight and the other is doglegged or 90*. Since you have an electric choke, drill them to what Kenth said. It depends on the pcv too.

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