The pressure a mechanical fuel pump creates is a function of the diameter of the diaphragm and the tension of the spring that pushes it. All the camshaft does is lift the diaphragm and provide the vacuum to pull the fuel into the pump chamber through a one-way valve. Some rebuilders install any old spring that will fit, with little or no attention being paid to the output pressure. I've seen some "rebuilt" pumps produce 10 PSI or more and cause massive flooding problems when the needle valve can't shut off the flow at idle. Once the engine speeds up a little the excess fuel gets burned quickly enough to avoid flooding at cruise speed.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!