you'll need the cav fueltank as the nova presumably wouldn't fit, but you deff need an injection tank as they have both send and return fuel lines as the injectino system sends excess fuel back to the tanks.
Just about all the carb vauxhalls have feed and return lines in the tank.
The difference with then injection tank (non internal fuel pump type) is that they have a special swirl pot type thing so the fuel pump gets an air free supply of fuel. The carb tank will work, just you may have problems if you have low fuel or give it some round corners.
BTW, you'll need the oil temp sender (back of the block by the starter motor), coolant temp sender (below dizzy), and i guess the GTE dizzy too for it to work.
Dunno if the places to fit the two sensors will be just plugged up or not there on your block though.
The standard dizzy should do, the nova gte is a fuel only ecu, it just gets its timing from the tach signal. use a die grinder to match the inlet manifold to the ports, an youll probably need a throttle cable off an injected astra. i had no problems running without a swirl pot as long as the tank was out of the red.