its like hp and torque are related--you can't have one without the other

In fuel pumps pressure is ditated by what kind of system you have--carbs needle/seats will only handle up to 5 or 6 lbs reliably and you need a pump that will supply the power demands of your engine-----of course in any system the plumbing has to be big enough to supply the 80, 100 gallons per hour rate

in efi systems---most of the oem throttle body systems work on 20 +/- lbs and the individual port systems will be upwards of 40 to maybe 60 lbs