dropped base air cleaner

[chevy art]

i have 408sbc in my vega. 10to1 forged pistons. 195 cc runners on the aluminum heads, solid roller aprox 600 600 on lift and aprox 250 duration at .050. and a rebuilt 850 holley. its on a single plane intake and that has created a clearance problem in the Vega. dont want to put on a hoodscoop and i just barely have room under hood for a 2 inch air filter if i cut the webbing out of hood over carb area. a dropped base air cleaner would do the trick. but i feel i would loose a nice chunk of horepower with the dropped base. but then i could use a 3 inch filter. i also thought of using a custom air filter top to help airflow. any input as to using a dropped base or not using one. any other air cleaner suggestions to help with this clearance problem thanks Art in NY

[Tom68]

This my mold for when we ran Cup Cars here, 830 Nascar Carbs.
Drops the bottom of the filter 2" below the flange, also angles it, with a 16" x 4" I believe there was no power drop, we were making around 660 HP back then, I wasn't present at the Dyno, left it with the operator.

Been meaning to add an L88 air filter base to my collection of stuff I'll probably never use.
.

20220519_164639.jpg

[KnightEngines]

I tested a K&N drop base with 3" element against a bare carb on a 600hp 365 cube engine a while back.
The K&N made 3hp more.

[HQM383]

Welcome to the land of compromises.

One of these

https://www.summitracing.com/search?Sor ... %20xstream

Or revisit intake manifold. What’s on there now?

Does the carb have a choke horn?

[rgalajda]

This is the one I used . Original equipment to a 1969 Chevelle BBC holley carb.

https://www.ss396.com/chevelle/ATE-3907.html

[skinny z]

This is the one I used . Original equipment to a 1969 Chevelle BBC holley carb.

https://www.ss396.com/chevelle/ATE-3907.html

How close would that lid be to the choke horn do you suppose?
I'm looking for a similar solution.

[rgalajda]

This is the one I used . Original equipment to a 1969 Chevelle BBC holley carb.

https://www.ss396.com/chevelle/ATE-3907.html

How close would that lid be to the choke horn do you suppose?
I'm looking for a similar solution.

I'll do some measurements and get back.

[weedburner]

I added a section to an existing drop base to make an extreme version...



Had to get creative for a throttle cable bracket, but the extreme drop allows me to show someone the top of a stock looking Carter/Edelbrock 625 without revealing the Crosshair nitrous plate below...



Grant

[F-BIRD'88]

This is the one I used . Original equipment to a 1969 Chevelle BBC holley carb.

https://www.ss396.com/chevelle/ATE-3907.html

How close would that lid be to the choke horn do you suppose?
I'm looking for a similar solution.

You want to remove the holley carb choke horn
on all of the aftermarket version holleys.
The old OEM muscle car holleys had a shorter choke horn height and different down leg boosters.

The aftermarket holleys all have the taller choke horn.
Cut it off or upgrade to the HP style centerbody.
(no choke horn)

[BillK]

I ran the Moroso drop base with a 3" filter on a 355 I drag raced for years. Car had an old school snorkel type hood scoop but I never liked the idea or running it without an air cleaner. Air cleaner made absolutely no difference. It was about 530 horsepower 355 in a 67 Camaro

[n2omike]

This company has a wide assortment of bases, tops and ram air inlets. Some nice stuff.
https://ramairbox.com/
I've used their parts/kits since the 1990's

[nhrastocker]

You want to remove the holley carb choke horn
on all of the aftermarket version holleys.
The old OEM muscle car holleys had a shorter choke horn height and different down leg boosters.

The aftermarket holleys all have the taller choke horn.
Cut it off or upgrade to the HP style centerbody.
(no choke horn)

You do not always need to remove the choke horn on a Holley.
In NHRA classes where we are only allowed to remove the choke mechanism but must keep the choke horn, we use the K&N Stubstack and can still use an air filter assembly.

https://www.knfilters.com/racing/stubstacks.htm

[F-BIRD'88]

You want to remove the holley carb choke horn
on all of the aftermarket version holleys.
The old OEM muscle car holleys had a shorter choke horn height and different down leg boosters.

The aftermarket holleys all have the taller choke horn.
Cut it off or upgrade to the HP style centerbody.
(no choke horn)

You do not always need to remove the choke horn on a Holley.
In NHRA classes where we are only allowed to remove the choke mechanism but must keep the choke horn, we use the K&N Stubstack and can still use an air filter assembly.

https://www.knfilters.com/racing/stubstacks.htm

The gm drop base is not "a air cleaner". It is lower..
Its lower than the moroso and others.

So....
The lid is too close to the choke horn.
The OEM holleys had a lower choke horn than the
typical aftermarket holleys do. Theres a difference.
QJets and carter eddy carbs are fine..

[rgalajda]

This is the one I used . Original equipment to a 1969 Chevelle BBC holley carb.

https://www.ss396.com/chevelle/ATE-3907.html

How close would that lid be to the choke horn do you suppose?
I'm looking for a similar solution.

It is a 2 inch drop base. I have measured 30/64" from the top of the air horn to the lid. I use a double gasket measuring .095"
You will need angle cut vent tubes like the factory carb. Easily done if yours are not angle cut.

Choke horns on aftermarket Holley were not all taller.
I have a 1969 Copo Chevelle Holley List 4346 , a 1971 Corvette LS6 List 4803 , 3310-1-2-3, Quick Fuel 770 cfm BR67258 plus others, that all have the same height choke horn within thousands of an inch, 1.36" to top of air horn.

Will also fit a newer holley's /and quadrajet if you bend/cut the front tabs in photo.
I personally do not like to mill off choke horns on a street carb , especially in cooler climates. There is little cfm to gain unless proper reshaping is done.

The other picture is the other style air horn, which incorporates the vent tube. This could obviously be reshaped easily.
Also 3310-1 aftermarket Holley had down leg ( dogleg ) boosters.
I hope this helps.

[skinny z]

It is a 2 inch drop base. I have measured 30/64" from the top of the air horn to the lid. I use a double gasket measuring .095"
You will need angle cut vent tubes like the factory carb. Easily done if yours are not angle cut.

I personally do not like to mill off choke horns on a street carb , especially in cooler climates. There is little cfm to gain unless proper reshaping is done.

I hope this helps.

About a half inch all told then.

I'll have to get to mine and measure as well. I haven't the deepest drop base but with the 4" filter element, I'm a good distance away.
I'm of the same mind about milling off the choke horn. Although not a Holley (old Barry Grant Speed Demon) it already has a nicely contoured entry.
I'd like to go back to a 3" element but don't want to strangle the air entry.

Now if I could find a work around for the goofy choke linkage that runs outside of the air horn rim, maybe I could reinstate the choke butterfly and save myself from all of that excessive fuel wash on those cold start mornings.

Thanks for checking out those dimensions.