Holley metering blocks and emulsion

[TT5.9mag]

Came across something I’ve never seen before and I’ve done more than a handful of these. I’m going through and building a carb for a friends stroker small block ford mustang street car. He provided the carb. Where it originally came from is unknown but it’s a complete Holley list 80570. The primary metering block has ZERO emulsion holes drilled. Block is numbered 6104-3. I have never come across this at all. Anyone else?
@Mattax
@Newbomb Turk

 

[TT5.9mag]

I just told the customer that this is a 570 street avenger and not the right carb for what he’s doing but I’m still questioning the odd emulsion package on the primary block.

 

[33IMP]

Factory OOPS ?

 

[TT5.9mag]

Factory OOPS ?

I have no idea.

 

[TT5.9mag]

Story is the carb couldn’t be tuned because it sat outside without an air cleaner. It had a bunch of trash in it and even though it’s wrong for the engine I so want to put it back on and try it now that I’ve gone through it.

 

[33IMP]

Not many hot rodders under-carb their engines.
I'm a over-carb guy myself. Ever since I put a 780 in place of a 600 on a warm small block chevy. Night and day difference.

 

[Mattax]

That's a funny looking stamp on the block.

Going from memory, either on RFS forum or the old Innovate forum people reported an unusual configuration in the Truck Avenger. I'd have to search old posts. I personally haven't had my hands on a street or truck avenger.

Lets talk about what we see.
I see a low idle restriction, a bleed in the dogleg, and maybe a small bleed into the angle channel.
Seems possible this has a emulsion tube in it. Look at the well plugs on top of the block.
In the mean time I'll see what photos I can find. Might have even posted some here.

 

[Mattax]

Yup. I'd have to dig up the details but this is a block from a Truck Avenger that someone posted and I marked up to show the wells.
The odd thing was that it doesn't connect the air well (and main air bleed) into the main well. I vaguely remember not getting a more in depth look about what makes it tick.

Here's a photo from Tuner of an emulsion tube removed.

Goes right in the main well and is fed air through the hole in the dog leg of the airwell.
The air well in this one looks like it also had e-holes but they are not drilled through. Or they shouldn't be!

 

[Mattax]

I thought I had one on a 4150 from my friend. Closest I see in my photo files is a Holley spreadbore that is still in my collection. Point is the top view shows the flat top of the brass tube flush wityh the top of the block.

 

[TT5.9mag]

So are we to conclude that the avenger series carbs don’t have emulsion holes in the blocks on the primary side? It sure looks like the block you posted in pic 1 post 8 looks to have no emulsion drilled.

 

[Mattax]

As far as I knew only the truck averngers came like that.
Here's a 770 Street Avernger primary block that someone posted, probably on RFS.

 

[TT5.9mag]

As far as I knew only the truck averngers came like that.
Here's a 770 Street Avernger primary block that someone posted, probably on RFS.
View attachment 1716447907

huh.

 

[TT5.9mag]

This one is definitely listed as a street avenger.

https://www.holley.com/products/fuel_systems/carburetors/street/parts/0-80570

 

[Mattax]

Do you think that block is the block it was sold with?
Need to find someone who has a messed with a few of them. I'm thinking maybe Mike who was on RFS, if he still particpates there.

What's the top of the block look like? All cups or are the main wells flush?

 

[TT5.9mag]

Do you think that block is the block it was sold with?

I do. I asked him if he ever took it apart and he said no.

What's the top of the block look like? All cups or are the main wells flush?

I left the carb at work. I will take pics of the top of the block tomorrow to show the plugs in the top. Best pics I currently have are below and it’s hard to see.

 

[92b]

I dynoed a truck avenger carb for a customer some years back and it was like in the picture, no emulsion holes. It ran good on the dyno.

 

[Bewy]

I see two emulsion holes in the dog leg area. They look to be well above the fuel level.

 

[TT5.9mag]

What's the top of the block look like? All cups or are the main wells flush?

 

[92b]

View attachment 1716448077

Looks like emulsion tubes.

 

[TT5.9mag]

I see two emulsion holes in the dog leg area. They look to be well above the fuel level.

The lower hole in the dogleg is a kill bleed. The upper hole is bleed air from the main air bleed. Neither of which I would call “emulsion”.

 

[TT5.9mag]

For reference only, here is another block I have here, numbered 5882. This block has emulsion tubes as well as emulsion holes.

 

[92b]

It's been quite a while now so I'm not 100% on this. When I called holley tech about the truck carb not having emulsion holes in the block ( I thought they were accidentally left out) they told me the truck carb was designed for off road, rock crawling and such where the truck was opperating at a high degree of angle. I told them that naming it a truck carb would lead people like my customer to think it was a carb for a pickup truck. He recommended one of there other models for a regular pickup truck application.

 

[Mattax]

So it looks like it has the emulsion tubes. I don't think you have to treat it differently than any other 4150 unless it behaves in way that requires investigating the e-holes.

 

[TT5.9mag]

So it looks like it has the emulsion tubes. I don't think you have to treat it differently than any other 4150 unless it behaves in way that requires investigating the e-holes.

As soon as I ran the numbers for a kit I realized it was a 570 and I told the customer it’s completely wrong for his application. I doubt I’ll get too much further in to it. In fact it may not ever go back on the engine. He did say he has a 318 that needs a 4 barrel so maybe I’ll get to tune it on that.

 

[Bewy]

You can call it a kill bleed but the fact is it is connected by the passage to the emulsion well, so the air is 'connected'.
Check out these Weber E tubes. Notice the difference in where the uppermost holes are. Some would be above the fuel level, some below.