https://www.ebay.co.uk/itm/Datsun-280z-engine/202753231772?hash=item2f3508cb9c:g:mBcAAOSwCzJdOwaz
Thought this might be of use to someone and worth an offer.
Is that filter mount from a 280ZX?
I'm guessing the head is either earlier (as with the flat tops) or has been machined for the fuel pump.