I did not change the chain on the 560 engine, just the rails and tensioner, as the 560 was only stretched 5 degrees at conclusion.

In contrast, after changing the 380 rails and tensioner, the chain remained stretched over 8 degrees, so I changed the chain also, for net 0 degree stretch.

I will change the 560 chain at 8 degrees - approx. 160k miles in my case. YMMV.