$50.99 USD
MSRP $78.59 35.1% Off
Free Ground Shipping!
In Stock & Ready to Ship!
Find a Dealer

K&N 56-9121 Custom Racing Assembly

Custom Assemblies > Custom Racing Assembly
Rating Star 1 Rating Star 2 Rating Star 3 Rating Star 4 Rating Star 5   5.0 out of 5 stars   1 Customer Review
  • Designed to increase horsepower and acceleration
  • Show quality with custom chrome top and base
  • Washable and reusable air filter
  • High air flow with excellent filtration
  • One year limited warranty
K&N Custom Air Filters for Single or Two Barrel Carburetors - K&N custom air filter kits are designed to boost performance from your carburetor while keeping the dirt on the outside where it belongs. These assemblies come with custom chrome top and base plates and the famous K&N High-Flow Washable Air Filter.

[More Information on Custom Air Filters for Single or Two Barrel Carburetors]

Product Specifications

Air Filter Height1.75 in (44 mm)
Air Filter MaterialCotton Gauze
Air Filter ShapeRound
Filter MaterialCotton Gauze
Inlet Diameter1.281 in (33 mm)
Mounting Hardware IncludedYes
Neck Flange1.281 in (33 mm)
Overall Height2 in (51 mm)
Product Box Height6.56 in (167 mm)
Product Box Length3.5 in (89 mm)
Product Box Width6.31 in (160 mm)
Product StyleCustom Assemblies
Replacement FilterE-3211
Top Material/FinishChrome
Top StyleChrome
Weight1.2 lb (0.5 kg)

K&N 56-9121 Custom Racing Assembly Product Reviews

Saturday, June 14, 2014 - Part 56-9121
I installed these filters on my 1979 Spitfire MK3 on the dual HS2 carbs together with richer needles, I used AAQ. The change in performance was dramatic, I suspect part was due to the car running rather lean on the original needles which were BO, but the filters do seem to flow air better. I have no access to a dyno but the performance increase was very noticeable on the road. MPG has also improved by about 2mpg. There are some own sides you can hear some induction noise, not much of a problem the Spitfire is not exactly quiet anyway. The car seems more susceptible to temperature variations and the idle falls off if it sits in traffic. I have put this down to the filters picking up more hot air directly from the manifold, I plan to fit a heat shield to help with this but it has not arrived yet so can't comment if that works. Since this is a hobby car the idle problem is not a big issue but if you were planning to use it on a daily driver it might be more of a problem. All in all I am very happy with the purchase.

Cambridge United Kingdom