OK, eDaddi--see you joined as a full member, great. Now you have access to our technical resources, limited as they may be for what you may be wanting.
Nobody is going to flame you on Unimog stuff here. Maybe if you attempted to turn a Pagoda into a rock climber, you may be flamed, but you are not...so welcome!!
...however you are really stepping into a dark arena, with many costly pitfalls ahead of you trying to do things that may not have been done before. If they have been done before, perhaps they were one-offs and not documented. Sometimes, also, there's a reason why things have not been done before. Many times people have tried and failed. I've seen many older cars that have been worked on over the years, and instead of trying to work with the original engine, or even a re-worked older engine, the restoration folks get a crate engine. Saw a restored 1937 Cadillac the other day, that originally had a 6 liter V12 in it. Instead of screwing around with that, the restorer put a modified LS2 engine in it from a modern 6 liter Cadillac CTS.
You are trying to put an old M130 motor into an even older Unimog chassis. You are perhaps wanting to experiment with cams as well. On top of all this, you want to run it on propane!
Unless you want to get caught in a quagmire, you may consider a plan using the scientific method. If you really want to do all of this, I'd suggest you construct an engine test stand that will allow you to run the engine outside of a chassis and test it on the stand when running. Back in Detroit where I used to live, there were all kinds of R&D places that had this kind of setup with advanced diagnostic equipment inside of controlled test cells. If you are a billionaire, you could hire some help and contract for a test cell. If you are not, well, you'll have to make your own!
The first thing you may consider after building the engine test setup is diagnosing the health and condition of the engine in its present state. No sense trying to experiment with cams, different carburetors, or even propane when the head needs a valve job, or your rings are shot, cylinders scored or any number of other engine maladies. Once you get the engine health diagnosed, and running properly, then you can experiment with cams, carbs and propane. I know that there will be some serious diagnostic equipment you'll need to test each change to the cam, ignition, fuel and more. You may have to search long and hard to find some of this stuff.
The scientific method will tell you do one thing at a time. If you do a bunch of different things all at once, you'll never know what the issue is when it doesn't work right.
Good luck! Sounds like a long, fun project for you!
