27.71" of head pressure = 1 psi of water, gas is almost the same in a car situation. SO if your tank is 14" below the tank, it will need to pull .5 psi to get it to the pump. More math makes the brain hurt....

1941 Taylorcraft
1968 Charger
1994 Wrangler
1998 Wrangler
2008 Kia Rio
2017 Jetta

I didn't do 4 years and 9 months of Graduate School to be called Mister!