As I understand it, the '79 clutch will not fit the '83 trans so that's not an option. I'm running the '83-style trans (I understand it's a Getrag) in my race truck and don't expect any issues. While the Mercedes-made trans is marginally stronger my understanding is that there isn't a LOT of difference between them. I mean, WHY would Mercedes install a trans that's too fragile behind their somewhat more powerful 616 engine? Unless you're doing a lot of drag strip racing I doubt there would be an issue.

Another thing to consider - I'm not sure that the transmissions are the same length so you may get into swapping driveshafts, crossmembers, replacing the rubber biscuits, etc. AND, the Mercedes trans is a TON heavier than the Gettrag which matters when you're shoving it up from under the car!

I'd buy a decent clutch for the '83 and fix what you have - I got my Sachs from Pelican parts. A consistent failure on these is the clutch slave cylinder so you may want to replace that while you're in there. It'll be a stinker to bleed but there is guidance on here for that.

Dan