Kinda hard to see the “fork” in this photo.
For those who do not know, the before mentioned “fork” is at a 10 O’clock position in photo and it blends in with his (bench, I think it is).
For cars using exhaust manifolds and pre-cats, the fork does line up (I can’t remember what, right now) to clock it to the exhaust manifold.
If you are using headers – I would like for you to do something before installing this part to block:
Snugly attach a header to that side of engine using two bolts. Take an oil filter and see if you can screw the filter straight onto the block (there might not be a thread for it at this point, if not no worries – just use your imagination).
If filter can attach to block with filter without using the adaptor – that route might be best (or preferred).
Next, screw a filter onto your adaptor, snugly.
Without using the bolt, see if the 90’ adaptor will fit on without header interference. If not, then screw the adaptor on (snugly) and see which method would be easier to change oil with.
Headers tosses a wrench in the works, when it comes to oil filters. Different headers = different solutions for the filter.
In your case, it is easier to figure this out before it all goes into the car (so to speak).
Trying to get this figured out, after installing headers (in car) can be fun, especially with oil dripping in your face.
BudW