Oil Filter Block Fittings

I would like to remove these oil cooler fittings and replace them with AN type.

I’ve made a half hearted effort but they didn’t budge. Before I do some damage, thought I might ask for some help.

How are they attached? Press fit? Threaded?

Thanks in advance for the insight.

-John

Just pushed in, with annular O-rings.

I did this, to the fittings on my hot rod.

Thank you, that’s exactly what I needed and I appreciate the pics.

-John