Dance steps, need some help!

[77cruiser]

If you make the threads just deep enough to get the screws flush you don't have to lock tite them.
Since you have a bunch of setscrews you can plug the UIAB & drill the air horn & make the bleeds ajustable to fine tune transition without taking the top off.

[Cadman-iac]

I'd go back to .048 UIAB.

Before I make any modifications to this bowl, I wanted to make sure I understand which way I should go with both the upper and lower idle air bleeds.
 As I'm reading this, I should go back to the original upper bleed size of  .048, and shrink the lower bleeds to something like  .060-.063, is that correct?

 I'm also going to go back to an IDCR size of .052+/- as Kenth suggested as well as slightly smaller idle tubes of .038.
 I'm also going to make the bypass air passages around  .040.
 This should get me back to a close to stock setup and then I can see what I need.
 Hopefully this will get me back on the right track.  What do you guys think?

[Cadman-iac]

If you make the threads just deep enough to get the screws flush you don't have to lock tite them.
Since you have a bunch of setscrews you can plug the UIAB & drill the air horn & make the bleeds ajustable to fine tune transition without taking the top off.

 You wouldn't have a picture of exactly where you placed your set screws in the air horn would you? I like that idea.

 Also,  i was playing around with some old junk bowls trying different ways of making the lower bleeds smaller. I gave the check ball method another shot, still don't like the results.
 Then I remembered that I had a box of aluminum hammer rivets, so I tried using those to fill the holes and then redrilling to the correct size. It actually turned out pretty good, but I'm still getting the brass set screws, I'd rather be able to remove the screws to change the sizes. My aluminum rivet method works if you don't have to go back and make it smaller again. It's not impossible, just difficult.
 Thanks for your help.
 Rick

[77cruiser]

I think it shows how in Cliffs book if you have it.

[Cadman-iac]

I think it shows how in Cliffs book if you have it.

 Yeah, I just found the picture in his book. I was just wanting to see how it looked from the top side.
 I'll try it on an old core I've got.

[77cruiser]

Good. When you thread from the top it's easy to get too deep.

[novadude]

I would be very careful with any kind of press-in solution on those lower idle air bleeds.  If a press-in bushing comes out, there could be bad consequences.  Make sure you have a good tight press fit with the rivets, as anything that is not very secure in the venturi / throttle bore makes me nervous. 

[Cadman-iac]

I would be very careful with any kind of press-in solution on those lower idle air bleeds.  If a press-in bushing comes out, there could be bad consequences.  Make sure you have a good tight press fit with the rivets, as anything that is not very secure in the venturi / throttle bore makes me nervous.

 Yeah, I thought of that, I used a punch tip inside the down channel from the bottom because it goes right behind the bleed hole and then drove the rivets in against it to ensure that they are swedged into place. The last thing I need is for one of these to go bouncing around inside a cylinder.
 But like I told 77cruiser, I'd rather use the set screws as they can be changed easily if need be. This was just a trial alternative in case I had no other option.

[novadude]

Using the punch in the down channel to back up and swage the rivet is a great idea. 

[Cadman-iac]

  Thanks Novadude.


 Another question, if you're changing a set screw in the air horn to calibrate and the carb is still on your engine, how can you keep the set screw from falling into the carb? Do you guys use a bit of grease on the end of the allen wrench, or some other method? What do you recommend?

 I have to use an over the fender creeper in order to reach the carburetor on my truck, one, because it sits high, and two, because my poor old titanium reinforced spine can't handle climbing into the engine bay anymore.

[77cruiser]

That's what I do, & if you drop it carb has to come off.

[Cadman-iac]

That's what I do, & if you drop it carb has to come off.

 I'll probably pull the carb off to swap any of these just to be safe. I've got the process down to a couple of minutes and two tools.

[Cadman-iac]

Since you have a bunch of setscrews you can plug the UIAB & drill the air horn & make the bleeds ajustable to fine tune transition without taking the top off.

 What transition are you referring to here? How does this work exactly?

 

[77cruiser]

Transition slot, smaller AB will richen idle curb idle can leaned out with the screws.

[Kenth]

I have found that the idle/low speed mixture is predetermined by the idle tubes/jets and the upper and lower air bleeds and any idle bypass air.
The amount of mixture, on the other hand, is determined by the channel restrictions and the mixture screws.
The off-idle slots acts like additional air bleeds above throttle blades and changes to idle mixture discharge nozzles when thottle blades passes the slots at greater throttle blades openings.

So you cannot get a leaner or richer mixture from the mixture screws at idle, only more or less volume of the mixture.