Its hard to see but the inside surface of the tensioner is uneven cast.
And they want you to mount it upside down, which puts the machined surface flat onto the bracket. Which is fine but then your outside nut is rested on the uneven cast part.
Please be advised, you will need to run a longer supercharger belt, move the factory timing pointer outward, and run a smaller idler pulley. (A 4AGE NA timing bel alternator pulley works decently when flipped around backwards and shimmed out a tad
oem
HKS or something pulley
