Custom Coordinate System - Y Axis only 1.5 x exaggeration?

[Justin_Shelton]

I use a custom coordinate system to make a simple grid of feet (x = distance in feet, y = elevation in feet) in order to create profiles of geophysical data in ArcGIS. Does anyone know of a way I can tweak the coordinate system to create a vertical exaggeration of the Y axis x1.5?