non mustang fuel pump
 

My pump was whining really loud so my girlfriends father gave me a ford fuel pump that he had kicking around. I'm not sure what it is out of but I'm sure it's not out of a stang. The car runs alright but I think it's lagging in the upper rpm range.

Would this pump have a lower output than the stock mustang one and be starving the car for fuel?

the fuel pressure dropped a couple psi but is still within spec.

I don't think that you want to use just any pump. I know it came out of a ford and it will probably work. But if I were you and was going through the hassle of dropping the tank, and such, I would be ordering me at least a 190 lph from summit. This way you know you will have plenty of fuel for any mods in the future. Unless you plan on a blower then I would get a 255.

Anyway, you need a new pump because it is close to dying when it is whining.