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Technical Holley Carburetor question?

Discussion in 'The Hokey Ass Message Board' started by Boneyard51, Feb 25, 2020.

  1. Boneyard51
    Joined: Dec 10, 2017
    Posts: 6,442

    Boneyard51
    Member

    I have searched all over and cannot find out what the numbers on Holley metering blocks mean! I know the basic differences in metering blocks, front vs rear, power valve vs no power valve, etc. What I want to know is there a chart some where listing the metering blocks calibrations? I have to assume that different numbers are calibrated in different ways? And are some interchange able? Never saw any info on this, and there must be hundreds of metering block numbers out there! Thanks in advance,








    Bones
     
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  2. squirrel
    Joined: Sep 23, 2004
    Posts: 55,944

    squirrel
    Member

    I have a Parts and Specs catalog from 1982 that lists the part numbers for the blocks for all the different list numbers that were around at that time. But no calibration info about them, or anything.
     
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  3. oldiron 440
    Joined: Dec 12, 2018
    Posts: 3,301

    oldiron 440
    Member

    Sometimes you can get the factory jetting from the Summit website.
     
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  4. Boneyard51
    Joined: Dec 10, 2017
    Posts: 6,442

    Boneyard51
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    Jim could you check to see what metering blocks were used on List # 2436 and 2437? Thanks!
    That’s ok Squirrel, I got that info just now on another thread! Bones








    Bones
     
    Last edited: Feb 25, 2020

  5. Boneyard51
    Joined: Dec 10, 2017
    Posts: 6,442

    Boneyard51
    Member

    Well..... I guess I have asked the unanswerable question! I have checked with most sources I know, and .... zilze! Noda, nothing! Really? The almighty Holley Carburetor that folks have put on their cars for years! And no one has a clue as to what the numbers mean on the metering blocks? That really amazes me! I always though this was the summation of all knowledge! Guess not! Lol








    Bones
     
  6. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 5,217

    2OLD2FAST
    Member
    from illinois

    About 20 years ago when
    I was tuning my 2x4 TR I called holley early on a Tues morning and got ahold of Art. He told me short of disassembly and measuring there wasn't any way to tell . He said once the metering block was separated from the carb , unless they were stamped with list numbers , there wasn't any reliable records . He sent me a handful of the small cup plugs so I could pull them and measure . It turns out on the carbs I was working on it really didn't matter as drilling out idle jets and modifying idle air bleeds wasn't really possible with my equipment nor was it warranted as the carbs did what they were supposed to do with a simple PRI jet change. You might try talking to AED carbs (new jersey ??) , I bought jet plates and extra kits from them and they were helpful with tuning info and had really good quality & prices
     
    Last edited: Feb 26, 2020
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  7. squirrel
    Joined: Sep 23, 2004
    Posts: 55,944

    squirrel
    Member

    are you waiting for me to answer? sounded like you already found the info.
     
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  8. squirrel
    Joined: Sep 23, 2004
    Posts: 55,944

    squirrel
    Member

    here you go, have fun

    num.jpg ill.jpg list.jpg
     
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  9. The large Holley book that I have has a part number listed for the metering blocks as does Jims above.Is a portion of that part number the same number as stamped on the metering block?

    I"m far away from any carburators to check at the moment.

    Maybe CarbKing will weigh in on this ?

    Oldmics
     
    Last edited: Feb 26, 2020
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  10. I've tinkered more with Rochester and Carter stuff over the years. But is there really that much metering going on in the Holley metering blocks themselves once you take away the jets and power valves? Is it just a matter of different air bleeds, emulsion tubes and maybe the idle circuits? :confused:
     
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  11. Beanscoot
    Joined: May 14, 2008
    Posts: 3,056

    Beanscoot
    Member

    "Is it just a matter of different air bleeds, emulsion tubes and maybe the idle circuits?"

    Yep, that's all it is.
     
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  12. Boneyard51
    Joined: Dec 10, 2017
    Posts: 6,442

    Boneyard51
    Member

    No, no, no. I posted that I had found the metering block numbers for my 2436 and 2437 carbs. The comment about the unanswerable question was aimed at “ what the numbers actually mean” . That is how is a certain metering block with a certain number calibrated. It jus seems odd to me that there is not a chart somewhere that lists the metering block numbers and tells us what was done to make this block different than another block. Hot Rodders have “ hot rodder” every thing on the planet it seems , except the lowly Holley metering block it seems! Lol








    Bones
     
    Last edited: Feb 26, 2020
  13. squirrel
    Joined: Sep 23, 2004
    Posts: 55,944

    squirrel
    Member

    I expect there was information about it at Holley, but for internal use only, not released to the public.

    I wonder if it's still around?
     
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  14. Boneyard51
    Joined: Dec 10, 2017
    Posts: 6,442

    Boneyard51
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    Thanks Jim, that is the first chart that I have seen, that actually told what metering block went with the 2436/37 carbs. I don’t have these metering blocks, so I am trying to figure out what will work in stead of these. Again thanks!

    Edit: I do have a bunch of Holley carbs with a bunch of different numbered metering blocks on them. I would just like to know if one of them would work on my 2436/37 carbs? And if so, which would work best? There has to be a reason there are hundreds on different numbers on metering blocks!?




    Bones
     
  15. Boneyard51
    Joined: Dec 10, 2017
    Posts: 6,442

    Boneyard51
    Member

    When you guys are talking about your “ big Holley “ book which one are you talking about? I went to E-bay and there are several books for sale there. Don’t know which is the best, here is a pic of my book, which doesn’t list the metering blocks, by the way!








    Bones E5DA70B8-2883-485D-965C-74E3D8774202.jpeg
     
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  16. squirrel
    Joined: Sep 23, 2004
    Posts: 55,944

    squirrel
    Member

    I am referring to a real Holley book. Got it from a friend, he was racing a lot in the 1980s.

    holley.jpg
     
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  17. DDDenny
    Joined: Feb 6, 2015
    Posts: 19,144

    DDDenny
    Member
    from oregon

    How about showing the page with numbers for a Holley #3245, was specific to the 66 Nova 327/350 hp engine.
     
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  18. Boneyard51
    Joined: Dec 10, 2017
    Posts: 6,442

    Boneyard51
    Member

    I kinda figured you had a good book! Now I’m going hunting for one. Looks like you may have opened a can of worms! Lol






    Bones
     
  19. Since I deal with 50s machines those 40 - 50 big blue Holley Master Parts Catalog is what I refer to.

    Mines worthless after the 59 model year.

    Oldmics
     
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  20. squirrel
    Joined: Sep 23, 2004
    Posts: 55,944

    squirrel
    Member

    327b.jpg 27a.jpg 327.jpg
    327c.jpg
     
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  21. DDDenny
    Joined: Feb 6, 2015
    Posts: 19,144

    DDDenny
    Member
    from oregon

    Very cool, thanks Jim.
    Here's mine.
    GM #3877413

    20151220_085847.jpg
     
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  22. I"m still in the dark as to if the Holley part number listed in these sheets is the actual part number stamped on the metering blocks?

    Oldmics
     
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  23. squirrel
    Joined: Sep 23, 2004
    Posts: 55,944

    squirrel
    Member

    Maybe Denny will tell us? :)
     
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  24. DDDenny
    Joined: Feb 6, 2015
    Posts: 19,144

    DDDenny
    Member
    from oregon

    I still need to go look at mine, not sure if the metering plates on mine are correct, that's my reason for asking.
    I think the Holleys destined for oem applications were consistently numbered, not sure about the aftermarket versions.
    By the way, for some reason, on that page, Holley shows the 3245 for Chevelles, not so.
     
  25. egads
    Joined: Aug 23, 2011
    Posts: 1,419

    egads
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  26. DDDenny
    Joined: Feb 6, 2015
    Posts: 19,144

    DDDenny
    Member
    from oregon

    These listings don't call out metering block numbers but I verified mine are correct from numerous qualified internet sources.
    I did learn that oem (GM at least) "service replacement" carbs used a different numbering system than the earlier versions.
     
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  27. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 5,217

    2OLD2FAST
    Member
    from illinois

    I gotta laugh ," numerous qualified internet experts" that's pretty much as non- descript as you can get......LOL ........kinda like " 7 out of 10 doctors recommend ". Too funny !!
     
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  28. DDDenny
    Joined: Feb 6, 2015
    Posts: 19,144

    DDDenny
    Member
    from oregon

    I hear ya, we all need a laugh now and then!
    Truth is, I didn't just pick this out of nowhere, I have followed this specific car/engine combination since the early 80's, I just don't carry every number around in my head like I used to so I needed a refresher.
    Most of us don't have the luxury of quizzing a neighbor or uncle that worked at GM engineering or on the assembly line in the 60's, they're just not around anymore.
     
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  29. I have no idea how Holley's part numbering system works. But is it possible they used a "production" part number for a metering block assembly which included specific jets and power valves for a specific O.E.M. application? They may have never offered this "production" assembly for sale as a replacement or "service" part. Instead, the correct bare metering block and the specific jets and power valves would have to be bought separately to assemble a "production" metering block assembly.

    In other words, a relatively small number of various "service" metering blocks, when combined with a larger variety of jets and power valves, could then be used to assemble a huge number of different "production" metering block assemblies for "service" or aftermarket use.
     
  30. squirrel
    Joined: Sep 23, 2004
    Posts: 55,944

    squirrel
    Member

    If I wanted to be helpful, I could make a list of all the metering block part numbers in that big book I have, and what they fit.

    but that's a lot of work.
     
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