what car?
asuming that its a sprinter, do you have a 4age or 4ac (guessing 4age seeing as you have an elec pump)?
if it is has an ADM tank (most likely, dosent have baffles). you should be using a surge tank in the system. incase you don't know, you then have a lift pump to fill the surge tank and a main pump that pumps it to the motor.
also "off the shelf" refures to a part that isnt custom, so majority of aftermarket part would be considered off the shelf. do you mean a factory one from another car? there would be several pumps that would be more than upto the job.
