I recently built a 410 stroker ('71 360, 040) and added the tensioner. I used a ProGear timing chain. After degreeing the cam, and ready for final front-end assembly (on an engine stand), I noticed the front crankshaft oil slinger plate was hitting the tensioner (at the lower front corner of the tensioner)... it would have caused trouble when the harmonic balancer would be installed... a constant rubbing of the oil slinger against the tensioner (in other words, the oil slinger plate would have been running at a constant slight angle while rubbing the tensioner). So, very carefully, using a Dremel grinding tool and masking all the area there, I ground away about 1/8" of the lower phenolic edge of the tensioner until I could see there would be sufficient clearance between the oil slinger and the tensioner.
I contacted Hughes Engines (where I had purchased most of the engine parts for the build), and they told me (besides saying they've never heard of such interference) that the tensioner was never intended, from the factory, to be installed on the LA engines... only to be installed on the Magnum-series engines (V6 and V8). I wish I had known that before; good thing I spotted the physical interference and resolved it before final assembly of the front end.
So, just a word of caution for final assembly -- inspect IF there is physical interference at the lower edge of the tensioner and the oil slinger plate... careful grinding clearance may be needed.