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Carburator casting numbers.

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Grim-Reaper, Sep 13, 2002.

  1. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Ok I have a weird one. I have a carb that I does not seem exsist. It does not seem to fit into the nice neat easy to figure out catagory.
    According to Dorian Yeagers web site http://www.dorianyeager.com/qjetdecode.html the carb is a mid 76. The casting number do not make a lot of sense and don't fit exactly into how dorian site say's they should. I spent over an hour at Auto Zone going through their books. I think I found the right rebuild kit. I found carbs one digit either side of this on (last diget of casting before and after).
    What I need to know is what this pig was bolted too so I can get an idea if the main jets are going to be too big for my 350 and I need to swap from the old carb.
    Here on the numbers
    17062040
    1896

    What is throwing me is the 6 as the 4th digit.
    Also this thing is filthy and I may have put a 2 as the fifth digit and it's supose to be a 7.
     
  2. txbluethunder

    txbluethunder 1/2 ton status

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    well if that digits a 7 instead of a 2

    Rochester R-4 17067040 80-85 Chev &GMC Truck

    www.carbs.net
     
  3. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Hehehe I just typed the casting number into Google with a 7 and it shows 78-85 truck and that's in dirrect conflic with the date casting of 1896= 189 day of 1976. LOL
    That's off here
    http://www.edelbrock.com/automotive/carb_qjet_ref.html
    See I believe it's pre 78 because this thing has no EVAP connections and I don't think it has a EGR connection. EVAP and heavy emmisions started in 78 on GM trucks.
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Any chance of getting a few pics up?

    There ahve been a few of these carbs popping up (lately) with no correlation to known stamped numbers.

    Here's one that will tell you for certain if its as late a model as you found in your search. Are the bolts Torx or Phillips head?
     
  5. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Glad you popped in Dorian /forums/images/icons/smile.gif
    Yep torx. That was throwing me also. Thought that was a 80's thing. The problem is the carb is deffinatly set up for around 76-77. No vent connection for the EVAP. It is set up for Hot air choke not a stove. Doesn't appear to have a timmed port for EGR. All that stuff say's pre 78 to me.
    I hope to lock my family in a closet tonight so I can get this carb rebuilt. I'll get you some shots.
    Could this be a factory replacement carb or something and the 6 is 86 not 76?
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    Well heres one for you. Is it the "square faced" early design, or is it the later angular front, with the small "dome" over the aneroid cavity? (front passengerside top on the airhorn)

    According to Roe's book, GM used some of the older type carbs with the "older" stamped in numbers on newer vehicles, and although it doesn't make sense, GM has re-used the exact same carburetor on two different model years, just re-stamped over one digit (1984 Hurst Olds and 1985 442 IIRC) so anything casting number wise is possible.

    Heck, in the later years (late 80's) the same stamped in number was used for multiple years, with NO change.

    I can't, for the life of me, remember how my '83 K5 carb was setup. I'm guessing it was set up with the big Evap fitting that came out towards the drivers side at a 45* angle, but I don't specifically recall it. I do know that it was an electric choke, and I *think* if yours was an '86, unless the choke was changed, it would be electric.
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    Well heres one for you. Is it the "square faced" early design, or is it the later angular front, with the small "dome" over the aneroid cavity? (front passengerside top on the airhorn)

    According to Roe's book, GM used some of the older type carbs with the "older" stamped in numbers on newer vehicles, and although it doesn't make sense, GM has re-used the exact same carburetor on two different model years, just re-stamped over one digit (1984 Hurst Olds and 1985 442 IIRC) so anything casting number wise is possible.

    Heck, in the later years (late 80's) the same stamped in number was used for multiple years, with NO change.

    I can't, for the life of me, remember how my '83 K5 carb was setup. I'm guessing it was set up with the big Evap fitting that came out towards the drivers side at a 45* angle, but I don't specifically recall it. I do know that it was an electric choke, and I *think* if yours was an '86, unless the choke was changed, it would be electric.
     
  8. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    It has the dome over the aneroid. It has the hot air choke though like a 77-79 would have. The Edlebrock page also shows this casting number and does indicate that it is supose to be Hot air.
    See it's weird. All the hook ups and date code say 76-79 but stuff like Torx, the casting number, aneroid, ect say early 80's pre the electric.
    Story of my life. I have a reputation here at work as the one that finds the weird stuff.
    I would think that somebody built the thing with a bunch of parts if the Casting number made sense but since the casting number is equally weird I don't know what to think.
    It ran fine when it came off but I just wanted to rebuild it before throwing it on my truck and make sure that the casting plugs are not going to leak, see what jets it had in it, see if the slosh baffle is there etc. I'm also converting it to electric choke.
    Autozone's books and computer drew a blank when we tried looking it up. Their books did show 17067039 and 17067041. Both of those had the same rebuild kit so I bought that kit hoping it's the right one.
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    Hve you converted one of these to electric? My dad had a HECK of a time making one of these work w/electric, but it could have started out as the intake mounted ones. Can't remember which, but it wasn't because he didn't know what he was doing, it was just a different setup that made it a hassle, moreso than you'd expect.

    Most cars got that dome in about '76, and most car carbs from then on out, until CCC ('81) had that, so it still doesn't rule out 70's, but I don't believe torx started until 80-81, as I've never seen any on '79 stuff, but all the CCC carbs ('81-up cars) used them.

    It *is* frustrating not knowing what it came from, but in the end I guess its not really important, I end up playing with all of mine anyways to "tune" them right. Luckily, the last one only took one jet change and I was set. Could probably tune more too, but I'm gonna spend my time getting the TPI going, not the carb : P
     
  10. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    I converted the one on my wifes 79 when I dropped the crate in. It didn't have the provisions for the hot air on the intake. Went very smooth. The problem I am having is finding the oil pressure swtich. Zone didn't list it but I go the guy pulling senders for GM's and he came up with what was listed as a Idiot light swithc but it has two termilas stick out of it and it's open with no pressure. Sure looks like the right part. Going to check it tonight with the air hose.
    Yeah I plan on FI one day. TBI is just fine for my trail truck.
     
  11. Blazer79

    Blazer79 1/2 ton status

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    Could it be possible it is a post 76 but the heavy duty version? which explains fewer ports? Maybe there's a separate section on the book for heavy duty emissions?

    Just a thought.
     
  12. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    I don't know. Its weird. I leaning towards it being a dealer replacment carb. The Torx bolts instead of philips heads is weird. THat's a 80's thing. Same with the Aneriod dome. I think even the 3/4 and 1 tons have the EVAP by 78. They may not have had the EGR till later and I know they were not included in the 1/2 ton regulations till after 78. I think they didn't get cats till 82.
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    Sorry it took so long, I wasn't anywhere near my Hollanders for the past two weeks.

    The 17067039 shows as a Chev or GMC truck, anywhere from 1980-1984, with engine vin M. (350, emissions class though?)

    Somewhat interestingly, the interchange, or also used number with that stamping, in the same vehicles, is "17080298", which seems to be a bit more inline with what you have, based on how its put together. Oddly though, it lists the 80-84 VIN M's as ALL being the 080 number, and NONE of them being that 067 number. 067 may have been some kind of service replacement for those trucks.
     
  14. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    hehehe It's one of them outer limits deals. I find the number sometimes but no cross refference to what it came off of. Even the rebuild kit I bought that was listed for the 39 and 41 carb didn't list any of the three in the instructions. I just checked the settings before I pulled it down. 9/32 float level just like most so I reset it at that. It had the right gaskets though. Just doesn't make sense. 82 up should all have evap connections and this one doesn't.
    The carb is a good runner. It's pretty smooth and no bogs. I can get a stumble out of it If I floor it then lift and floor it but I have to try to make that happen. In normal driving it never happens.
    Hay have you ever seen a carb with a high idle cam that is smooth? It doesn't have the steps that most have. It's really nice with the electric choke. It just idles down real smooth. There is maybe 200rpm change from start to full warm. No tapping the throttle to get it to drop high idle needed at all.
     
  15. dyeager535

    dyeager535 1 ton status Premium Member

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    Well, maybe someday you will run across the number somewhere : )

    I've never really paid close attention to the idle cams with the electic choke, certainly makes sense to have a smooth one. Would be kind of nice. I played around with my mech choke quite a bit when I was setting it, decided 1500 is a nice first step, 1000 for second, and then the 600 curb idle.

    Still gonna be happy when that no longer is an issue with TPI : )
     
  16. imiceman44

    imiceman44 1 ton status

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    Hey guys, I am not sure if you are still on this thread but one thing you should remember is that it could be from a later model 1ton truck since they were not and still are not required to have EGR and most other smog equipement, their smog levels are much more tolerant so they are built the easiest way to get more power, that is why on my diesels I go with 1 ton parts and get more power, since diesels are not checked in California. /forums/images/icons/smile.gif
    IceMan
     
  17. dyeager535

    dyeager535 1 ton status Premium Member

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    You know, its often claimed that they get more power, but does anyone have any factory HP/TQ numbers to back that claim up?

    My guess as to the different emissions levels is A)less of a certain GVW on the road means less polution (there are way more 1/2 tons than 1 tons for instance) and B) reliability...I'm not so sure on reliabilty, but for instance, EGR, costs nothing in power, as its not working at idle, and not working at full throttle. You get better cruise MPG, so why, besides reliability, would you NOT want it?
     
  18. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    EGR is nothing new. I had a 70 sub that had a 65 327 in it with EGR. EGR and EVAP do not hurt performance at all. The 1/2 ton trucks went to EGR, cats and EVAP by 78. That I know. The cali trucks went in 74 I think. The 1 tons didn't get cats till later. I think they got them in 82. Even so I think they did get the EVAP and the EGR in 78 like the rest of the trucks. There is no reason not to have put EVAP and EGR in the other trucks at the same time. Unless they had a big block there was really no difference between the 350's they used other than maybe cam.
    This carb is set up for a vehicle built between 76 and 78. It has the hot air choke and GM ran the divorced choke through 75. It has not EVAP or EGR connections. The Build date, according to the info Dorian has, say's it was manufactured in 76. What doesn't make sense is the casting numbers and the fact that it has allen bolts. Both of those indicate after 81.
    Now this car has been rebuilt. It had RTV on the casting plugs. It's possible that it was rebuilt by a company and at that time the bolts were swapped.
    That still leaves the screwy casting numbers. The only thing I can come up with is this was a replacment carb that was actually manufactured in the 80's for a mid to late 70's vehicle. It's the only thing that makes sense and would explain the torx bolts.
     
  19. 76chevy

    76chevy 1/2 ton status

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    Hey Grim,

    My original 76 carb had torks bolts in some places. I just went outside to look for it but forgot I just barely threw it away. The body was cracked so I figured why keep it. I kept a few parts off of it.

    My truck was labeled as a HD. It had the divorced choke with the hot air thing comming off of the headers also.

    The Hot Air thing is/was just hooked up to a vacume port on the carb. Guess I should plug up that vacume port. Hot air choke still works, even though it isn't connected to the headers .

    I also have a PCV valve and choke vacume hooked up. I think the only other vacume port is for the timming.

    Sounds like a similar carb. Wish I could find the numbers. When I got a rebuild kit from Checker we had to look through their books for a while.

    I bet you would be safe with most kits since they cover tons of different carbs. Anyway you're the resident carb guru here so I will now bow down and worship before I leave.
     
  20. dyeager535

    dyeager535 1 ton status Premium Member

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    With the previous post in mind, maybe if you can get www.carbs.net (think thats carbs unlimited, up here in the Seattle area) a picture of the gasket needed, they USED to match up your airhorn gasket with their stockpile. A little pricey per gasket, but since just about all other rebuild stuff in the "kits" is the same, if you need one, $3 or so isn't bad for one gasket that is right.
     

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