The W116 has the M110 right?

The M104 should fit dimensionally, but you would probably need custom brackets for the two engine mounts and the trans mount.

Drive shaft might even need to be custom...

This might not be easy...

__________________
2006 BMW M5 "Heidi" @ 109,000 miles
2005 MBZ C55 AMG "Lorelai" @ 165,000 miles
1991 MBZ 300E "Benzachino II" @ 165,000 miles
1990 MBZ 500SL "Shoshanna" @ 118,000 miles

(On the hunt for a good used M103 engine as of 6/10/23, PM me if you have one to sell!)