The vast majority of baffeled tanks currently available are not capable of providing air free fuel unless they are at least half full.
Even modern EFI cars are having issues with air bubbles getting into the high pressure fuel lines. Most serious EFI systems are using a surge tank to suplement and eliminate the air bubble problem on the high pressure side.

I am using a surge tank in my '68 Barracuda with a stock fuel tank and exterior mounted pusher pump, it can be run as low as 2 gallons with no air getting in my high pressure side.

It also keeps the high pressure plumbing much shorter, as it is mounted at the front of the car.