My understanding is the 17 mm “nut” on the face of the NA tensioner gets in the way of the belt
This is why the SRT tensioner doesn’t have that “nut” on the face of the tensioner. The tensioner is released via the pulley bolt stem. The bolt holds the pulley and both the bolt and pulley are different

on the NA you can remove the bolt, on the SRT you cannot remove the bolt stem, the pulley is held in place with a nut on the pulley bolt stem.
if the SRT tensioner bolt stem is loose, the pulley is toast. There is no way to tighten the bolt stem

the tensioners shown on rockauto and autohaus are for the NA

The tensioner listed will not work on the SC Engine.