To answer the questions here my 78 has 349,780 miles and the 81 has 211,450 miles. I have driven the 78 since it had 254k miles. I do not know if the timing chain had ever been replaced and I never measured the stretch. I had a local MB shop look and listen to the 81 and he condemned the timing chain right off. Said that racket at start up was the chain getting ready to destroy my engine. I then pulled the tensioner and it was not looking too good either, so I decided the chains were only about $89 each, the slide was another $25, and the tensioner was $88. There were other costs, little gaskets, oil change, new filters, etc..
Not a bad repair to gain a little relief from that threat. And why not do them both? Might speed it up a bit.
I used the swaging tool to put them together. I had read here where you can use a ball peen and backing and that works. I don't know about getting the master link together though. The master link has the outer part that needs to be pressed on. The tool has a fitting to set the link in place and then tighten it onto the rest of the master link. That part would be difficult at best without the tool. I was given loan of the tool localy.
I had read several threads about doing this job and they were most helpful. I used small vise grips to clamp the new chain onto the cam sprocket and vise grips to clamp the old chai in place. Then just roll it in in increments. Set and made sure I had the TDC marked and pulled the fuel injectors out. Would not want the engine backing up in the middle of this.
To tell you the truth I was just short of terrified to take this project on. The only experience I had with timing chains was on my first engine repair. There I was at age 14. Put rings and bearings on an old Honda 160cc motorcyle. Then the timing chain.
You guessed it, I missed the marks and bent up the valves and pretty much wrecked that one. I swore off timing chain work at that point.
Larry, I think your analysis is going to prove true. The 81 will now need the IP timing adjusted. Thank you.