There is an article called "pump it down" and it described how to give more road feel and less overpower of the pump by using a thicker washer between the pump body and pressure regulator valve.
The idea is that the farther out the valve sits in the pump, the less pressure the pump put out.
He is referring to that article thinking maybe upping the pressure on your pump may be possible by using a thinner washer.
Here's the article
http://www.moparaction.com/tech/beep/PUMP_IT_DOWN-re-v1.4.pdf
