K&N FAQ's
Still looking for CFM chart for the filters. I found this on K&N's site. :
HOW DO I FIND/CALCULATE THE PROPER FILTER SIZE FOR MY CUSTOM APPLICATION?
SHAPE
When fitting a conventional round filter on top of your engine-such as a carburetor, central fuel injector, or throttle body fuel injector-a large diameter, short filter will provide more airflow than a small diameter, tall filter. For example, a 10-inch diameter, 2-inch tall filter will provide more airflow than a 5-inch diameter, 4-inch tall filter. Where space permits, the height of the filter should be between 1/5 and 1/4 of its diameter.
The shape of the filter is less important if the application calls for a remote mounted filter, which includes many late-model fuel-injected vehicles.
SIZE
Use the formula below to compute the minimum size filter required for your particular application. The usable portion of the filter-the effective filtering area-is calculated by multiplying the diameter of the filter times pi (3.1416), multiplying by the height of the air filter in inches, and then subtracting .75-inch. We subtract .75-inch to compensate for the rubber seals on each end of the element and the filter material near them, since very little air flows through this area.
Keep in mind, these formulas are the minimum size requirement. To provide an even greater volume of air to the engine, install the largest filter that will fit in the space allotted.
For an 0-360, you have Effective Filtering Area=360*3000(for a small cushion)/20839=51.83 square inches
If you are sizing a round filter, use the following formula to determine the height of the filter.
Then, Filter Height=51.83/(7.75*3.14) +.75 = 2.87 inches. The 7.75" diameter is for the E-3450 Vans uses which is only 2.5" tall...so my math must be wrong somewhere.