A039A4: AeroCarb Air filter

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K&N A039A4 is what I have installed on my Aerovee with AeroCarb. The original PN is no longer available, but K&N E-3120 is still sold and may work though it will be tight based on my measurements. I did a search for other filters with similar specs online but I didn’t find any reputable options.

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Note: based on another discussion thread, the E-3120 is a little bit short (only 2” high vs. the old E-4310 at 2.75” high). So the 3120 may not provide sufficient airflow.

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I wonder if they increased the size of the filter on AeroInjector models. The filter on my AeroCarb measured approximately 3.5 inches in diameter and 2 inches tall. The through bolts that hold the filter and the base in place are only about a quarter inch away from the exterior moldings.

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There is a discussion of the Baldwin PA4557 disposable paper element, it’s nearly twice as long, with the same diameter, longer AN3 bolts will be required.

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Another option, might be able to use the stock bolts, Speedway Motors paper element, their part number 91011004, only two inches high though.
http://www.speedwaymotors.com/Speedway-3-7-8-Inch-Paper-Air-Filter-Element,4262.html
This seems to be a common size for two barrel hot rod carbs. Speedway also has a washable element version like the K&N E-3120.
http://www.speedwaymotors.com/Speedway-3-7-8-Inch-Washable-Reuseable-Air-Filter-Element,4264.html

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I recently installed a K&N RU-1900, went right over the intake bell of the AeroCarb and clamped down tight

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Thanks to all who posted other alternatives. My original filter is 20 years old but it does seem to be in decent condition. I run K&N filters in most of my cars and motorcycles so I was able to clean and reoil it. I’ll see how it goes and I’ll investigate other options people have listed if needed.

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