Easy one - fastener specs

Here's a guy replacing the belt tensioner, it will give you an idea about how far the bolt should stick out the back of the tensioner, my guess 25mm to 30mm

[ame="http://www.youtube.com/watch?v=E--Hz75a0TM"]How To Install Repair Replace Serpentine Belt Tensioner Dodge Ram 02-08 5.7L Hemi 1AAuto.com - YouTube[/ame]

Regards,

Joe Dokes