[Early_S_Man]

The air cleaner system on an early 911 engine is part of the tuning that matches the cams, equal-length headers inside the heat exchangers, and the intake tract tuning that extends from the intake valves all of the way to the long inlet horn of the air cleaner assembly ...

So, if the right side of the housing popped off/loose, you suddenly upset the pressure waves involving intake reversion pulses that extend above the velocity stacks of the Webers ... and that sudden change probably upset the torque that was being delivered, and the responsiveness of the engine to throttle inputs.

The intake noise increase on one side is the best clue I have ... and, torque produced at the bottom end will be higher with air cleaner properly seated, sealed, and with the intake horn in place,as opposed to just open Webers with nothing above the velocity stacks!