The spray angle is 153* on a VP bowl.
Here's a page of bowl shapes and dimensions that Weston has so graciously put up on PB:
[ame="http://s358.photobucket.com/user/westonmerril/library/Piston%20Info?sort=6&page=1"]Piston Info Photos by westonmerril | Photobucket[/ame]
Mark.