Constant fuel pump voltage?

[85burb]

I have put this in this area cause i tend to think more of you may be running electric fuel pumps then other sections on here. I have a question...I have just installed a summit (looks just like the holley) elec fuel pump in my truck in preperation for my engine swap. The pump sounds like the rpm changes a lot. I mean when truck is at idle is a lot slower the if i idle it up a bit. That i beleve will change my fuel psi to the regulator and will intern change my fuel psi to the carb. I would like to know if there is any way to make pump have a constant speed. Or i may just be crazy. I am having a hard time getting my psi at the carb to stay constant. If i start it cold and the fast idle cam is kicked in it is at 9 psi but when it warms up it is less. I beleve it to be something with the voltage at the pump. Any help on this would be appreciated.