does this 360 t chain look too loose?

The V8s never used them - it was for the V6s originally because of the different number of valve events in the same 720° cycle. If you go to the dealer and ask for a timing chain tensioner for a 3.9L V6 & they'll be able to find and order it. It's also available from the aftermarket like Sealed Power, TRW, etc. Auto Zone's site has them too. I usually get mine from mancini racing or summit.