The K&N Stubstack reduces turbulence, improves metering accuracy. Increases the airflow by reducing restriction. Straightens and speeds up air-flow.
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
|650 CFM||28 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
Holley 2300 Series Stubstack 85-0210
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.
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
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
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
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.
|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|
|0-4777 **||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|
|0-4778-1 **||4150||700||0-7009||4160||600||* Indicates dual feed fuel bowls|
** Indicates dual accel. pump & dual feed bowls
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.
|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|
K&N Custom Chrome Assemblies by part that are compatible with Stubstacks 85-0200, 85-0210 and 85-0700 ONLY!
These Stub stack filters are legal ONLY for racing vehicles. Not applicable, nor intended for use on emission controlled street or highway vehicles.