I have the Walker AirSep on my Cummins 6BTA 370 and it "is" actually a K&N filter. It's stamped K&N on the end of the filter. Made by K&N for AirSep. Custom sized for the AirSep system. Tried to replace through the auto parts supply store .. no go. Walker knows what they're doing there.
1018 hours on my '02 and have replaced it 2X. Works for me.
Searching for a 35 + ft. DE / cruiser/fishing
current boat 2002 Albin 28TE w/6BTA 370
The isuzu was 226 hp and the metal cage under the foam filter rusted, all of the powder coating and rust went through the turbo and killed the compressor blades. here is all the info for the filter i ordered
Universal Filter (Cleanable, 8-ply Cotton, Red Oil): Flange ID 3, Top OD 5.25, Element Height 6, Top Style: Solid Black Urethane
I would remove that metal screen. I have heard of more than one that has ingested that screen and caused some problems. You may have to use a rubber coupling and some plumbing to get the filter on the intake.
Wound up, I was looking at building something to run a aftermarket filter on my motor similar to the setup you have there and was told NOT to run my crank case vent directly plumbed into the elbow like that, you are pulling way too much vacuum on your crankcase. Just some sort of passive suction like aiming the vent at the filter or maybe adding on of those small valve cover K&N filters on a tee in the crank vent hose.
Dunno, when i first had the boat the went was aimed at the air filter and it made a mess of the filter and area around it. I know the mist from the ccv will be going to the after cooler and fouling it over time but it was what i went with, and i didnt see any adverse affects. I should have put a parker ccv filter on it but alas the boat is sold now.