Although I think port injection would be a immune to G-effects I also highly doubt the 1.0 g that a Cobra road race car pulls would have any real effect on fuel vapor mixture entering the cylinders as the intake valve opens and the piston retracts, sucking the fuel air mix in. It just doesn't stay in suspension more than a nanosecond before a cylinder grabs it from the intake.
Example of an FIA on track:
https://www.youtube.com/watch?v=xhsGzD3vNX8