what goes here?

[Sparkie67]

Hi all
Got a question for the people who have stripped kzte heads off.
From previous posts I have mentioned that I think the heads gone.
I bought a spare "good" one from a forum member.
The question is, at the non drive end of the cam there is a machined half circle in line with the cam. What seals in the shape. Also do the cam bearings not have journals like the 2.4 head.
Put some pictures up so you can see what I mean.
Should have it gas tested next week and know for certain if head needs to come off, but would like this one ready to go with all the correct bits.
Thanks

[Albannach]

There's a matching half circle in the old head. It needs sealed in place.