To clarify:

M116 = 3.5, 3.8, 4.2
M117 = 4.5, 5.0, 5.6

The M116 and M117 were available side-by-side in just about all model years, though not always in the US.

Only some 3.8l M116s have a single row chain and possibly only US/NorAm models. All 3.5l and 4.2l M116s have double row chains.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD