Ok my cousin picked up a used whipple for a 03-07 gm fullsize with LS motor, it has the newer single belt front braket, i have found the tensioner but i need a part number for the idler and i also need a heigth measurement of the spacers that go behind the belt tensioner and idler pullies! Any help would be great!! Thanks again!

heres a pic of what i have:


you can see the spacers i need in this photo:

 

Sorry i don't have a whipple anymore but you could measure the height to the pulley on the whipple and subtract the width of the pullies to get the size of the spacer.

 

If its anything like the 8.1l kit then you need one of these in the 3" smooth variety.

http://www.dayco.com.au/products.aspx?G=1787&P=1520