Ive had the same question, or similar at least, my Telstar has the 8 Valve SOHC motor (yay... 8 valves... It had 7 once as one had broken... Good times) and I've always wondered, the bore of the 2.0L carb engine and 2.2L fuel injected engine are exactly the same so I always wondered if the 12 valve head would fit on it. I think it does, and the only mod would be to get a 2.2L timing belt instead of a 2.0L. I think as well the intake manifold bolts straight on without mods as the bolts are in the same spot. And the carby doesn't have a clue what head its delivering fuel too!
I think in NZ they had a 2.0L Fuel injected version with 16 valves, thats the engine you mention I think. In which case its the same block as ours with a different head. I think the bore is the same which means there is no problems there. However Im not sure if it uses exactly the same fuel injection setup, but I dont see a reason why your intake manifold wouldnt fit onto it, they designed these engines to be cheap to produce so I imagine the bolts would all be in the same spot. And the
ECU probably wouldnt know what head was on it tbh. Its not that good!
The other question I had is converting my car to fuel injection is relatively simple, HOWEVER, my car is automatic, its a 3-speed vacuum controlled auto, and if you disconnect the vacuum line it relies soly on revs alone which is sometimes bad. Is there a spare spot to plug a vacuum line in on the fuel injection intake system? One right on the left closest to the gearbox? If so thats where my vacuum line goes!! Which means I can ditch these STUPID carbys and convert to injection without having to change the trans as well!
EDIT: I just thought of something, are these engines non-inteference engines? IE they have grooves in the pistons to prevent valve striking if a belt breaks? Because if so the grooves will not be in the right spot, and I think thats only okay as long as the belt doesnt break, but then again it might not be okay!