To my knowledge, the tensioner was only factory installed on the Magnum engines... NEVER on an LA engine.

I recently built a stroker LA 360, and with the tensioner installed, I caught the site of physical interference of the front SLINGER hitting the lower corner pad of the tensioner. I had to carefully die-grind away about 1/8" from the bottom of the tensioner lower corner pad to have clearance between the SLINGER and the TENSIONER.

NOTE: I later called Hughes Engine, whom I had purchased nearly all the parts for the engine, and described with pictures the interference... I was told, simply, that the TENSIONER was NEVER factory installed on any LA series engines. That kind of disturbed me... because there should have been a warning, or caution, included in the TENSIONER package when installing it... to observe for possible interference with the SLINGER and grind clearance to the TENSIONER lower pad if needed.