I'm basicly just duplicating a build i found in carcraft. In the build they installed a windage trey. As i was shopping around today i was informed by a shop that a windage trey would cause you to loose horse power. How could this be?

 

It could be that the shop didn't understand that you meant windage TRAY.

It could also mean that it's time to find a different shop. The whole point of a windage tray is to prevent viscous oil from clinging to the crank and keep it in the oil pan where it belongs. I'm not sure how that hurts HP.