Obviously when you start on this sort of project you have to sit down and have a conversation with yourself, an honest conversation about what you need to do. The question you start with is the bottom line, how much is it? I have a project planned on an old Ford F 500. It is pretty much nothing except a body. On top of the cab there are three old air horns, but that is not a working part of the deal. They are not any use. I will have to go on the world wide web and figure out where I can get some others like them. It is not that big of a deal though. It is something you can find pretty easy. Of course it is actually just as well that the thing is only a body. That way I can just build a modern truck and put this body over the top of it after I get it to look right.
I know some guys who work at the Volvo plant and I am sort of thinking that I could probably get them to help me with a chassis and perhaps they can even get me an engine. Obviously that would be a real modern truck and it would be a very expensive way to go about it. However this would also be the simplest thing for you to do and you would have a truck that was totally reliable and capable. It would at least be as good as any other truck that you could buy. It would not have the sound you would be looking for obviously. It is not as though these old trucks have some really distinctive sound though. They had diesel engines for the most part and they sounded like dump trucks.