milling off choke horn

[chevy art]

does anyone know if there were any real tests or dyno pulls on carbs with and without the choke horn on or off. we have been diascussibg this very thing this week in relation to dropped air cleaner bases and many have suggested to mill the carb choke horn for better air flow. thanks Art in NY

[1980RS]

I can tell you this, My 750 HP vacuum sec Holley with the HP no choke main body against my Avenger 770 without a choke blade ran within .002 of each other, so IMO it makes no difference. I still think the choke plate causes problems. I don't cut them off anymore.

[F-BIRD'88]

Most do not dyno test with the air cleaner installed.
Nor dynotest at car speed ,as installed. underhood.

[BOOT]

Been discussion before, think the trick was to epoxy the top or use a substack meant for a milled body. I wanna say bout 39cfm was the gain claimed by the HP style body kits Proform/Quickfuel/Holley.

When I installed a Proform MB on my 4779, made a nice difference just driving around But I have no track or dyno data just SOP

[Ishiftem]

Not a Holley but a Carter afb. Removing the choke plate was the big gain. Removing the choke tower gained about a 2% cfm gain on the primary bores. Not really a big deal.

[steve cowan]

does anyone know if there were any real tests or dyno pulls on carbs with and without the choke horn on or off. we have been diascussibg this very thing this week in relation to dropped air cleaner bases and many have suggested to mill the carb choke horn for better air flow. thanks Art in NY

My opinion is if you have to use a drop base having no choke horn must help.
I don't believe a carb draws air from above it comes in from the side as in a radius that why a bell mouth base works well usually.
You won't see a choke horn on any performance carb .

[bill jones]

---here's a link to a story and a few photos I did years ago about Holley 4 barrel choke horns and air flow testing


http://www.ryanbrownracing.com/Bill_Jones_Page_4.html

[steve cowan]

---here's a link to a story and a few photos I did years ago about Holley 4 barrel choke horns and air flow testing


http://www.ryanbrownracing.com/Bill_Jones_Page_4.html

Thanks for sharing Bill,
Big gains in epoxy top and thin throttle shafts.
When you flow tested did you do each venturi separately?
I am curious on your results from primary to secondary because of shape differences.
Did you do a before and after on running engine?

[bill jones]

---there's big gain's between the small primary and large secondary's of quadrajets
---and I use a lot of epoxy on the quadrajet air filter base to mold and shape the primary's and the secondary's to get a decent increase in carburetor flow---without even touching the carburetor

--never really had any way to test the small increment gains before and after---except everybody who got the improvements were always happy to pay me

[bill jones]

---I was trying to show a picture of a quadrajet air filter base--but I'm to stupid to figure out how to attach a file

[Tom68]

---I was trying to show a picture of a quadrajet air filter base--but I'm to stupid to figure out how to attach a file

If on a PC, drag and drop to your post, click on 'place inline'.

[1980RS]

---here's a link to a story and a few photos I did years ago about Holley 4 barrel choke horns and air flow testing


http://www.ryanbrownracing.com/Bill_Jones_Page_4.html

Thanks for sharing Bill,
Big gains in epoxy top and thin throttle shafts.
When you flow tested did you do each venturi separately?
I am curious on your results from primary to secondary because of shape differences.
Did you do a before and after on running engine?

Your work on that carburetor is impeccable, very impressed.