Got it in. Since I had already removed the old one, pulling was not an option but I tried cutting the old one and reinserting to use as a 'snake' but it wouldn't go in. Finally took out the ECU and inserted the new one in through the cab quite easily, then discovered that two of the screws...
Might try again with tape, I've looked at repair manuals for the 80 online and no mention of hood cable anywhere. It probably does go behind the battery box, maybe more to the side than under it and back up again.
Would appreciate some advice on installing a new hood cable. I tried to route the new cable through the firewall grommet but it won't go in from there the engine side, tried taping to the old one inside the cab prior to removing the old one but it got stuck in that ridiculously small grommet...