880 vs 3120

[Normzilla]

It's the space between the carb box on most of the old Stihls (and the 461) which I think it's the principal cause of clogged filters (it's way better on the new units (261/441/362).

But you're right, there's no air injection on the 3120.

Maybe a good ported 395 will be enough for this kind of job?

Never ran a Stihl that didn't pull dust through the filter. Every job I have to shake out Stihl filters, they are half plugged before lunch time. Location of husky filters on top, vs where the chips deflect is a big cause on Stihl I feel plugging quicker. The black hd2 I have had great luck with. But Stihl weakest point I feel filtration.