Factory Ford SVO had a EEC-IV ECU that you could buy direct from them. It was intended to piggyback on the existing EEC-IV. It was designed to piggyback and override the programming in your existing ECU. It was basically a fully-functional EEC-IV that was also fully programmable. It could also be used by itself, as a standalone ECU.
To port inject a tunnel port, I'd try a spider intake and mount the injectors back a ways from the ports and tubes, giving the sprayed mixture a good chance of getting into the 'flow'. Having the injectors smack bang next to the port isn't as critical as some might tell you. As long as they're in individual intake runners, well on the way to the port, they should work ok. But I haven't injected a tunnelport, so I don't know that from actual experience. I have injected an engine where the injectors were a solid 8 inches from the intake/head interface and that seems to work alright.
Good Luck