How Much PSI does the Stock TBI Fuel pump push?

 

Would imagine between 10-14 psi...

 

Just to clarify, the pump doesn't determine what pressure your fuel system runs at, the regulator does. If you just pinched the line on a TBI pump it would pump up to 90 psi or better. What your looking for is a volume at a certain pressure, the stock pump can barely keep 12psi with the volume demand of an LO3. This is why the TPI pump is so popular, a TPI pump was designed to deliver enough volume to feed a 350 at 43 psi. A pump is capable of more flow at a lower pressure, so a TPI pump will pump a whole lot more at 12 psi. It's the whole P1*V1 = P2*V2 equation at work. Keep in mind for that equation to work you have to be in the same units.