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K&N Stubstack® Air Filter

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         40 CFM

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

Custom Assembly with Stubstack

"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

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
List No.         #       Rating
0-4412         2300       500
0-6425         2300       650
0-7448         2300       350


#85-0210

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.


#85-0500

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.


#85-0400

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. 


#85-0600

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.


#85-0200
Carburetor   Model    CFM
List # #              Rating		 Carburetor   Model    CFM
List # #              Rating		 Carburetor   Model    CFM
List # #              Rating
0-1848-1     4160     465
0-1849       4160     550
0-1850       4160     600
0-1850-1     4160     600
0-1850-2     4160     600
0-1850-3     4160     600
0-1850-4     4160     600
0-2818       4150     600
0-2818-1     4150     600
0-3310 *     4150     780
0-3310-1 *   4150     780
0-3310-2 *   4160     750
0-4118 *     4150     725
0-4452-1     4160     600
0-4452-2     4160     600
0-4548       4160     450
0-4776 **    4150     600
0-4776-1 **  4150     600
0-4776-2 **  4150     600
0-4777 **    4150     650
0-4777-1 **  4150     650
0-4777-2 **  4150     650
0-4778 **    4150     700
0-4778-1 **  4150     700
0-4778-2 **  4150     700
0-4779 **    4150     750
 0-4779-1 **  4150     750
0-4779-2 **  4150     750
0-4779-5 **  4150     750
0-4780 **    4150     800
0-4780-1 **  4150     800
0-4780-2 **  4150     800
0-4780-3 **  4150     800
0-4781 **    4150     850
0-4781-1 **  4150     850
0-4781-2 **  4150     850
0-4788 **    4150     830
0-4788-1 **  4150     830
0-6109       4150     750
0-6299       4150     390
0-6299-1     4160     390
0-6619       4160     600
0-6619-1     4160     600
0-6895       4150     390
0-6909       4160     600
0-6919       4150     800
0-6979       4160     600
0-6979-1     4160     600
0-6989       4160     600
0-7009       4160     600
0-7009-1     4160     600
0-7154       4160     600		 0-7410       4150     340
0-7411       4150     370
0-7448       2300     350
0-7985       4160     600
0-7986       4160     600
0-7987       4160     600
0-8004       4160     600
0-8005       4160     600
0-8006       4160     600
0-8007       4160     390
0-8156 **    4150     750
0-8162 **    4150     850
0-8181       4160     600
0-8804 **    4150     830
0-9002       4182     600
0-9040       4160     600
0-9210       4160     600
0-9219       4160     600
0-9254       4160     600
0-9379 **    4150     750
0-9380 **    4150     850
0-9381 **    4150     830
0-9626       4160     600

* Indicates dual feed fuel bowls
** Indicates dual accel. pump & dual feed bowls 

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 No.    CFM rating   Choke Type     
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


#85-0700

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

Part #           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"
 

These Stub stack filters are legal ONLY for racing vehicles.  Not applicable, nor intended for use on emission controlled street or highway vehicles.

Copyright 2008 K&N Engineering, Inc. All Rights Reserved.