Pictures would be nice
Shit, i think we might have crushed the last 85 a few months ago! SHIT!!!Use a '85 turbo head, it has the smallest combustion chamber (42cc versus 44cc for all other c900 / 9000 2.0 heads) so higher compression ratio again.
The '85 intake cam lobes are meant to be ofset slightly so that one valve opend and closes just before the other to introduce a 'swirl' into the cylinder. I have no idea if this is of any value whatsoever!
But you must ditch the 85 exhaust cam, keep your original NA cam in there.