[Avmaviator]

Our FAST EFI system will be mounted in the collector, outside the car, as it was recommended by FAST and my engine builder. On the dyno it ran great. And we saw the same AF numbers on the two different banks. The dyno had an O2 sensor on the other side, also in the collector, to compare readings between the EFI sensor and the dyno sensor (and also left and right like I mentioned).

Unless something is going wrong on one side due to a mechanical issue or something, you should be getting correct information for tuning the whole engine by using only one side.