Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

which holes to measure???

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jbh7052:
Hello all! I just bought a rebuild kit along with primary/secondary rods, jets, float and a few other misc. items. he ask me to get him some measurements and he would recommend some changes if necessary! problem is I am lost as to which measurements he is needing ??? he specifically as for "upper/lower idle air bleeds, then the idle tubes, DCR's and bypass air". I have ordered his book but it will not make it here by this weekend and I cant look at it on the work bench without dying to work on it! can anyone point these locations out for me please? I tried to post a picture of the main body but I could not get it small enough to fit the requirements. Sorry!  carb#7045213

429bbf:
if your carb savy. you will understand this if not it;s going to be hard . the idle tubes and the dcr are located in the main body just to the front of the screw holes . the idle tube is a 2 piece tube(a brass tube with a brass collar at the top)very hard to measure unless you have a long set of drill bits. the restriction (what you are asked to measure )is about 2-1/4 inches down it would be somewhere around .035 or so. the dcr are right next to them . they are down in the housing about 1/4 in and are small brass inserts .measurement anywhere from .039 to .055 . these are very generic measurements you need to get within a.001. the bypass air is located in the throttle body . under the butterflies . usually coming in from the front at a 45 in line with the front mounting bolt holes . it may not have bypass air but it should . (make sure to go down in the bypass hole a ways for the restriction . its usually back in there a little ways. the upper idle air bleed should be a hole at a 45 angle that is just below the dcr leading to the venturi. the lower idle bleed would be close to the bottom of the venturi . size anywhere form .050 to .o70. you want a total of appox. .140 . example 60+80. 70 +70 THEY DO NOT HAVE TO BE THE SIZE. man i hope i didn't confuse you I'm sorry if i did.fwiw.

jbh7052:
Thank you so much 429bbf! that will get me rolling!i really appreciate you taking the time to spell it out for me. I don't mind doing research for info but the "STUFF" I was finding on the web was just stuff. Hope you have a great evening and thanks again! :D

429bbf:
sorry for a little confusion the upper idle air bleed should be just ABOVE the dcr if it is in the fuel bowl . some carbs have them in the air horn . (do not get the idle air bleed and and the main air bleed confused .) also it should have said THEY DO NOT HAVE TO BE THE SAME SIZE. I LEFT OUT SAME. the main thing your looking for is about .140 total.your little holes in the fuel bowl that feed the 4 barrel tubes should  be about .030  your accelerator pump discharge holes located in the air horn should be appox..026 the restriction is back in there a ways so pay attention.your little holes that you can see from the top with the top secondary flaps shut should be ..036your secondary tube restriction appox..036 i would give you all the technical names but that would maybe do more harm than good.remember all these sizes are approximate..hth

jbh7052:
thank you again 429 bbf! I was a little confused with the main air bleeds and idle but I think I have it! thank you for clarifying! you can sit back and laugh at me know...doubt I was the first but man I felt dumb...I pushed a drill bit down the idle tube and it got stuck! flush with the top! finally gave up and pushed it down further. drilled it and pulled it out...sure glad Cliff put those in the kit he sent me! anyway I was just getting ready to send this to Cliff. tell me what you think.
idle tube           .040
upper air bleed  .093
lower air bleed  .063
dcr                   .052
idle bypass        .099

my original air tubes are about .004 larger than the one's he put in my kit?? thanks again for looking at this! I appreciate it. I don't want to leave Cliff hanging so should I go ahead and send this to him as well? he was gonna let me know what to do with these measurements to meet my engine needs based on the info I gave him. have a good evening!

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