Holley Air Horn Question

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SpeedThrills

SpeedThrills

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If I cut the air horn off of my Street Avenger 770, will there still be threads to hold the air cleaner stud?
EDIT: I’ll remove the stud and see if I can see or feel down in there. And, see if the stud will thread down enough.
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There's only about 3/4" of thread. Looks like I should have the machinist mill around the vent tube and the casting where the stud is.
 
Or just cut along side of the boss and grind smooth. Biggest concern is keeping everything clean or complete disassembly and then cut/mill/grind/clean and reassemble. I would also assume 3/4 of thread engagement on a 1/4" all thread is plenty. That is 3x the diameter = 15 threads. The wing nut has much less thread engagement.
 
Best if you loctite the stud in, but not with the permanent stuff.
 
8E60B106-6C8C-4FED-84E8-8FB63E7B588F.png

Close up, better pic. After you cut off the choke horn there is lots of smoothing that needs to happen. And you need to fill the slot for the choke linkage or unfiltered air will pass through.
 
How much flow is actually gained with that particular mod?
 
Never flow tested one but some good data here; Bill Jones Page 4
Plus here in California I’ve never had a use for a choke so they all get machined off.
 
TT5.9mag said:
Never flow tested one but some good data here; Bill Jones Page 4
Plus here in California I’ve never had a use for a choke so they all get machined off.
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I've never had a hooked up choke on any carbureted vehicle I've ever owned. Thanks for the link. I'll check it out.
 
I find it interesting that someone who obviously knows a good bit about flow would use JB Weld anywhere near gasoline, since it is not imprevious to gasoline. Some good information there, otherwise.
 
That’s ^^^^ funny.
I think the relationship between the air cleaner lid (especially with a drop base bottom) and the top of the choke horn and their proximity to each other, when installed and running in a car is where the big airflow differences will be seen.
 
TT5.9mag said:
That’s ^^^^ funny.
I think the relationship between the air cleaner lid (especially with a drop base bottom) and the top of the choke horn and their proximity to each other, when installed and running in a car is where the big airflow differences will be seen.
Click to expand...
Yeah, I've said this before, but in the 60s, GM had a huge R&D program on airflow and air cleaner design. When their patent finally ran out on what they were making, Moroso picked up and ran with it. Those old 14" Moroso air cleaners don't just look cool, they straighten, smooth and direct airflow right into the carburetor. You can look at most an GM air cleaner from the late 60s pretty much until EFI and see the design.
 
RustyRatRod said:
Yeah, I've said this before, but in the 60s, GM had a huge R&D program on airflow and air cleaner design. When their patent finally ran out on what they were making, Moroso picked up and ran with it. Those old 14" Moroso air cleaners don't just look cool, they straighten, smooth and direct airflow right into the carburetor. You can look at most an GM air cleaner from the late 60s pretty much until EFI and see the design.
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Yea, almost every air cleaner dyno test, comparison I can remember reading about, that Moroso air cleaner ruled the roost. The one with the domed top lid and radiused base.
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207EDBBB-B37B-4D81-AFCF-38ADD1520E54.png
 
71GSSDemon said:
Or just cut along side of the boss and grind smooth. Biggest concern is keeping everything clean or complete disassembly and then cut/mill/grind/clean and reassemble. I would also assume 3/4 of thread engagement on a 1/4" all thread is plenty. That is 3x the diameter = 15 threads. The wing nut has much less thread engagement.
Click to expand...
I'll disassemble and clean, for sure.
When I cut the air horn off, there will be no threads, but that's addressed by cutting around the a/c stud boss.
TT5.9mag said:
View attachment 1716153031
Close up, better pic. After you cut off the choke horn there is lots of smoothing that needs to happen. And you need to fill the slot for the choke linkage or unfiltered air will pass through.
Click to expand...
I'll leave the bosses, stud and vent tube, thanks. I took the choke flap off long ago. I sealed the rod hole then.
TT5.9mag said:
That’s ^^^^ funny.
I think the relationship between the air cleaner lid (especially with a drop base bottom) and the top of the choke horn and their proximity to each other, when installed and running in a car is where the big airflow differences will be seen.
Click to expand...
This is why I want to remove the air horn. I don't know if it will improve air flow, but it can't hurt. I have 1" clearance between the lid and the front (higher part) of the air horn. I can't put a taller filter in it because I only have between 5/8" and 3/4" from the top of the air cleaner to the hood. It has a 3" tall element now.
RustyRatRod said:
Yeah, I've said this before, but in the 60s, GM had a huge R&D program on airflow and air cleaner design. When their patent finally ran out on what they were making, Moroso picked up and ran with it. Those old 14" Moroso air cleaners don't just look cool, they straighten, smooth and direct airflow right into the carburetor. You can look at most an GM air cleaner from the late 60s pretty much until EFI and see the design.
Click to expand...
It has an old gold Moroso on it. It doesn't look like the one TT5.9mag shows, though. I think it's from the 70's. It was on a friend's garage wall for years. It probably precedes the design of the nice one TT5.9mag shows?

My back's bugging me now. When I get this done, I'll follow up.
Thanks all!

Mine:
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1697212472675.png
 
RustyRatRod said:
How much flow is actually gained with that particular mod?
Click to expand...
It may not be all about air flow, there may be increased signal to the boosters and less pressure drop over the top of the carb. Plus your air filter housing top should be 3 inches from the top of the carb.
 
Post #18 is blatant promotion of the link the poster provided.
I don't know FABO's policy regaerding this, but it seems something should be done.
 
SpeedThrills said:
Post #18 is blatant promotion of the link the poster provided.
I don't know FABO's policy regaerding this, but it seems something should be done.
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Like a big ******* RED X
 
mopowers said:
AI bot? Look at their previous posts.
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I just hit Report in the lower left corner of the post.
Thats the type of stuff its for.
A mod or Admin will check it out and if they agree, it will disappear, as will the 'member'.
 
Mattax said:
I just hit Report in the lower left corner of the post.
Thats the type of stuff its for.
A mod or Admin will check it out and if they agree, it will disappear, as will the 'member'.
Click to expand...
Duh! I was looking for something like that. Couldn't see it for looking!

Post is gone now. :thumbsup:
 
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