just a thought... why not have two injectors per intake port, only one would fire at a time, but you would be able to use a normal 6 cyl controller firing in the correct firing order. The port/chamber doesn't know or care where the fuel is coming from. Fuel is fuel whether it came from a carburetor 12 inches away or an injector 2 inches away. You would gain better metering and atomization. You could even aim the injector towards the port you want to feed. The two intake valves in the shared port are not open at the same time.