I don't think Mercedes ever offered the 380 engine with a manual trans, so you are really in the weeds on that one. It's hugely unlikely that the pieces off the 280 would fit.

The diesel has a better chance but still very long odds. You would need to find out if there is an engine plate to mate the bellhousing to the engine and sleuth around for common part numbers for the clutch and flywheel.

There is at least one post on converting a diesel to a 5-speed and that might help you.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe