Quote:
Originally Posted by TNTaylor
I have a Kirkham 427 street cobra with a Shelby 427/468 engine with a Holley 850 CFM Ultra XP carb. Currently I have a 9" K & N round air filter which I would like to replace with a 14" x 3" round filter. Given I have a street cobra, my car has no hood scoop.
What I need help on is how I can figure out how much space I have, or lack thereof, to fit the bigger filter. Perhaps a straightedge from one side of engine bay to the other, or make up a 1/2" thick 14" round piece of rigid styrofoam temporarily adhered to the top of existing air filter. Then slowly close the hood.
Any suggestions?
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You need a
K&N 66-3040 unit. I've used this on several of my FE powered Cobra replicas (2-ERA's, 1 Contemporary, 1 Unique). If the air filter clearance is still a bit too close for your comfort, you can replace the 14X3" air filter with a 14X2.5" to 14X2.75" filter (there are four or five height incremental K&N filters available).
Now, with that said, before you spend any money, you need to see exactly what CFM worth of filter assembly you need to properly feed your engine.
Using the simple formula
A= effective filter area
CID=engine displacement
RPM=maximum RPM expected
Using the CFM formula of height X diameter x 6 x 3.14
Also keep in mind that the 14" extreme top flows 500cfm by itself.
Hope you find this helpful.
Sincerely,
Bill S.