Holley 1920 Metering Blocks?

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EvilTuna66

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I have what looks like an early Holley 1920 I found at the junkyard with the float, bowl cover and a few linkages missing. I replaced all of those but one of the check balls and the brass ring around it were missing from the metering block. I found a stripped down 1920 at another yard and put that metering block in my carb. Both carbs were early models on different 64 Darts so I figured they might work about the same.

I guess my question is...Can you swap Holley 1920 metering blocks if they're off of similar carbs on similar cars?



The carb I'm using had a big main metering jet, with the number 641 stamped on it. The one in the block I swapped in is a number 57. With the 57 jet, it stumbles on acceleration and fades in and out but has power. With the big 64? jet it accelerates fine but idles very rich and doesnt have much top end but is smooth.

Should I continue to mess with the jetting, or is swapping metering blocks a bad idea in general? I did replace the accel. pump and gaskets so I dont think its leaking anywhere.
 
you should be perfect at a 57... id you try to clean out the block before installing them? they are notorious for getting junked up...
 
EvilTuna66 said:
I have what looks like an early Holley 1920 I found at the junkyard with the float, bowl cover and a few linkages missing. I replaced all of those but one of the check balls and the brass ring around it were missing from the metering block. I found a stripped down 1920 at another yard and put that metering block in my carb. Both carbs were early models on different 64 Darts so I figured they might work about the same.

I guess my question is...Can you swap Holley 1920 metering blocks if they're off of similar carbs on similar cars?
yes

The carb I'm using had a big main metering jet, with the number 641 stamped on it. The one in the block I swapped in is a number 57. With the 57 jet, it stumbles on acceleration and fades in and out but has power.

its stumbles because your idle air bleed it to big, needs to be about .035"

With the big 64? jet it accelerates fine but idles very rich and doesnt have much top end but is smooth.

idle AFR is all idle mix screw and idle/low speed air bleed. if you close that bleed up and then adjust your mix screw you'll be good. the 64 is so rich that your actually losing power.
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EvilTuna66 said:
Ok! I thought thats why it was losing power. How would I go about closing that idle air bleed?
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wel if your lucky you have a screw, if not your going to have to solder the hole and then use a pin drill to open it up.

and if you still have the old PV, "economizer" parts add the gasket from that to the new one (double stack), mine seems to open around ten and should be around 6"...
 
I'm not sure exactly where that is to be honest. I've just never gotten that in depth with a Holley 1920. I'll try to find a diagram to figure out where the idle air bleed is. I know I used to have a late 60's one that had a little screw by the float bowl on the side by the needle and seat. But I know this one doesnt have it. Its an early 60s one.
 
EvilTuna66 said:
I'm not sure exactly where that is to be honest. I've just never gotten that in depth with a Holley 1920. I'll try to find a diagram to figure out where the idle air bleed is. I know I used to have a late 60's one that had a little screw by the float bowl on the side by the needle and seat. But I know this one doesnt have it. Its an early 60s one.
Click to expand...

yep that's the one... I think I have some pics on the home computer.
 
If you wouldnt mind posting them that would be great. I really appreciate all the help. So if I dont have the screw, I have to solder the idle air bleed and resize it to about .035? I'm not sure where it is on my Holley since theres no screw. Would you mind posting a pic? I know theres a small hole near the bottom edge of the float bowl sort of near the accel pump. But I'm not certain thats what I'm looking for.

Also, under heavy throttle it seems to gain and lose power like when you're running out of gas. Is this a lean out caused by the air bleed, that only goes away with the 64 jet because its so rich?
 
This carb was on a souped up '64 Dart that looked like it was mildly customized in the 80's. I did get a whole exhaust from manifold to glasspack off of it so that was cool hahaha. For some reason the little linkage for the the accelerator pump was set on the last hole for the largest shot of gas. When I rebuilt it I just put it on the middle hole since most of the carbs I've had were in the middle. I wonder if I should have left it alone?
 
EvilTuna66 said:
This carb was on a souped up '64 Dart that looked like it was mildly customized in the 80's. I did get a whole exhaust from manifold to glasspack off of it so that was cool hahaha. For some reason the little linkage for the the accelerator pump was set on the last hole for the largest shot of gas. When I rebuilt it I just put it on the middle hole since most of the carbs I've had were in the middle. I wonder if I should have left it alone?
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i set mine on the smallest shot from the middle and gained 1 mpg lol... though it went from just flicking the peddle on cold start to three pumps before i fires. hot start its half a crank.
 
EvilTuna66 said:
If you wouldnt mind posting them that would be great. I really appreciate all the help. So if I dont have the screw, I have to solder the idle air bleed and resize it to about .035? I'm not sure where it is on my Holley since theres no screw. Would you mind posting a pic? I know theres a small hole near the bottom edge of the float bowl sort of near the accel pump. But I'm not certain thats what I'm looking for.

Also, under heavy throttle it seems to gain and lose power like when you're running out of gas. Is this a lean out caused by the air bleed, that only goes away with the 64 jet because its so rich?
Click to expand...

ok here is the screw (if you have it, it can be covered by lead)
1920_air_bleed_screw.jpg


now this pic is the idle bleed (Head Side). yours could be completely leaded over, small, or to large. if you have to drill it out you need to break down the carb and pull the idle mix screw out and blow the crap out of it.

1920_Open_Air_Bleed.jpg
 
Man thats awesome. Thanks you for all your help. I think my screw is just leaded over so I'll see if I can get to it but thanks again for clearing all that up. I'll let you know how it goes.
 
EvilTuna66 said:
Man thats awesome. Thanks you for all your help. I think my screw is just leaded over so I'll see if I can get to it but thanks again for clearing all that up. I'll let you know how it goes.
Click to expand...

if you have the screw try 4.5 turns out
 
Yep, that seems to have fixed the off idle hesitation problem I was having. All that time I never knew that adjustment was possible. Thanks again for all your help.
 
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