K&N Stubstack®

The K&N Stubstack reduces turbulence, improves metering accuracy. Increases the airflow by reducing restriction. Straightens and speeds up air-flow.

INSTALLATION:
The K&N Stubstack is designed to increase the airflow of carburetors, by decreasing the restriction around the choke horn. The stubstack fits inside the air cleaner housing and slides snugly down over the choke horn. Install holding nut finger tight and use Loctite or 3M to seal. When installed on some models, there may be a slight gap at the base, however this is normal and will not affect the performance of the stubstack. Due to space limitations between the choke horn and some air cleaner baseplates, the stubstack has two thin spots in the casting. These will sometimes crack or chip slightly, but does not affect the performance. Because carburetor castings vary, the stubstack will not fit all carburetors. Check the list numbers for proper application. On some carburetors that are listed, it may be necessary to alter certain areas on the stubstack. The polyurethane material is easily filed and sanded.

AIR FILTER APPLICATION:
The stubstack is designed to only work effectively with K&N Filtercharger™ elements and 360™ custom air cleaner assemblies. If the stubstack is installed in an improper housing, the performance may actually drop! The minimum height above the stack needs to be at least 1-1/2" for proper operation. See bottom of webpage for compatible K&N custom assemblies.

FLOW BENCH TEST RESULTS
As Tested By Hot Rod Magazine

MODEL CARB. INCREASE
650 CFM 28 CFM
850 CFM

DYNO TEST: 5,000 RPM
STOCK PAPER ELEMENT: 295.4 H.P.
WITH K&N STUBSTACK/FILTER: 304.6 H.P.

"The original STUBSTACK™ hi-performance air horn will increase your engine's air flow up to 40 cfm with this simple bolt-on."

Hot Rod Magazine

Custom Assembly with Stubstack


Holley 2300 Series Stubstack 85-0210
Holley 2300 Series Stubstack 85-0210

HOLLEY 2300

Fits most Holley 2300 Series carburetors. The Stubstack is designed to fit 2 barrel popular models within this series. Holley carburetor list numbers are stamped on the choke horn.

Carburetor Model CFM
0-4412 2300 500
0-6425 2300 650
0-7448 2300 350

HOLLEY Square Bore with Milled Choke Horn Stubstack 85-0500
HOLLEY Square Bore with Milled Choke Horn Stubstack 85-0500

HOLLEY Square Bore with Milled Choke Horn

This stubstack is designed to be used on Holley 390-850cfm square bore carbs (4150/4160), that have had the choke horn milled off, but do not use an air cleaner. The full radius design helps to increase the airflow for drag racing. Will also hold down the base plate of a cold air scoop. Will not work with K&N Custom Chrome Racing Air Cleaners.


HOLLEY Square Bore with Milled Choke Horn Stubstack 85-0400
HOLLEY Square Bore with Milled Choke Horn Stubstack 85-0400

HOLLEY Square Bore with Milled Choke Horn

This stubstack is designed to be used with Holley 390-850cfm square bore carbs (4150/4160), that have had the choke horn milled off and still use an air cleaner. Eliminates the need for hand polishing and radius work. Will work with all K&N Custom Chrome Racing Air Cleaners, including Tall Velocity Stack Air Cleaners.


Holley 1050 & 1150cfm Dominator Stubstack 85-0600
Holley 1050 & 1150cfm Dominator Stubstack 85-0600

HOLLEY Dominator

This stubstack is designed to be used on Holley 1050 & 1150cfm Dominator carbs. Will not allow use of a standard air cleaner housing, but it will hold down the base plate of a cold air scoop. Straightens airflow and helps even out the flow to all four venturies. Decreases the restriction around the throttle bores.


HOLLEY 4150 & 4160 Stubstack 85-0200
HOLLEY 4150 & 4160 Stubstack 85-0200

HOLLEY 4150/4160

Fits most Holley 4150 and some 4160 Series carburetors with high and low choke horns. The 85-0200 is designed to fit 4 barrel popular models in this series. Holley carburetor list numbers are stamped on the choke horn. See the below chart for complete carburetor list numbers.

Carburetor Model CFM Carburetor Model CFM Carburetor Model CFM
0-1848-1 4160 465 0-4779-1 ** 4150 750 0-7410 4150 340
0-1849 4160 550 0-4779-2 ** 4150 750 0-7411 4150 370
0-1850 4160 600 0-4779-5 ** 4150 750 0-7448 2300 350
0-1850-1 4160 600 0-4780 ** 4150 800 0-7985 4160 600
0-1850-2 4160 600 0-4780-1 ** 4150 800 0-7986 4160 600
0-1850-3 4160 600 0-4780-2 ** 4150 800 0-7987 4160 600
0-1850-4 4160 600 0-4780-3 ** 4150 800 0-8004 4160 600
0-2818 4150 600 0-4781 ** 4150 850 0-8005 4160 600
0-2818-1 4150 600 0-4781-1 ** 4150 850 0-8006 4160 600
0-3310 * 4150 780 0-4781-2 ** 4150 850 0-8007 4160 390
0-3310-1 * 4150 780 0-4788 ** 4150 830 0-8156 ** 4150 750
0-3310-2 * 4160 750 0-4788-1 ** 4150 830 0-162 * 4150 850
0-4118 * 4150 725 0-6109 4150 750 0-8181 4160 600
0-4452-1 4160 600 0-6299 4150 390 0-8804 ** 4150 830
0-4452-2 4160 600 0-6299-1 4160 390 0-9002 4182 600
0-4548 4160 450 0-6619 4160 600 0-9040 4160 600
0-4776 ** 4150 600 0-6619-1 4160 600 0-9210 4160 600
0-4776-1 ** 4150 600 0-6895 4150 390 0-9219 4160 600
0-4776-2 ** 4150 600 0-6909 4160 600 0-9254 4160 600
0-4777 ** 4150 650 0-6919 4150 800 0-9379 ** 4150 750
0-4777-1 ** 4150 650 0-6979 4160 600 0-9380 ** 4150 850
0-4777-2 ** 4150 650 0-6979-1 4160 600 0-9381 ** 4150 830
0-4778 ** 4150 700 0-6989 4160 600 0-9626 4160 600
0-4778-1 ** 4150 700 0-7009 4160 600 * Indicates dual feed fuel bowls
** Indicates dual accel. pump & dual feed bowls
0-4778-2 ** 4150 700 0-7009-1 4160 600
0-4779 ** 4150 750 0-7154 4160 600

Edelbrock Square-Bore Carburetor Stubstack 85-7000
Edelbrock Square-Bore Carburetor Stubstack 85-0700

EDELBROCK Square-Bore Carburetors

Fits Edelbrock Square-Bore carburetors. The Stubstack is designed to fit almost every model within this series. This Stubstack straightens and speeds up airflow, reduces turbulence, improves metering accuracy and increases airflow by reducing restriction. Available for the Edelbrock part numbers. Will also fit some Carter AFB models.

Model CFM Choke
1400 600 cfm electric choke
1404 500 cfm manual choke
1405 600 cfm manual choke
1406 600 cfm electric choke
1407 750 cfm manual choke
1411 750 cfm electric choke

Performance Increase Comparison

K&N Custom Chrome Assemblies by part that are compatible with Stubstacks 85-0200, 85-0210 and 85-0700 ONLY!

K&N Assembly Diameter Total Height
60-1180 (w/vent) 11" O.D. 4 1/2"
60-1190 11" O.D. 6"
60-1200 (w/vent) 11" O.D. 6"
60-1210 (w/vent) 11" O.D. 7"
60-1220 11" O.D. 7"
60-1260 14" O.D. 5 5/8"
60-1270 14" O.D. 6 5/8"
60-1300 14" O.D. 4 3/4"
60-1310 14" O.D. 5 3/4"

Note: Legal in California only for racing vehicles which may never be used, registered, or licensed for use upon a highway. See knfilters.com for CARB status on each part for a specific vehicle.

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