Beautiful looking engine and transmission (and truck frame), is that yours during restoration?
That looks exactly like the spool setup that is used in a 1984 or newer Volvo 740 series. Since that is the case, Volvo 740/760 cruise control parts would definitely be one option for a way to get started on building a system (at least the mechanical pieces might be of use, maybe not so much the electronics)
Here is a good picture of the complete cruise control kit for 82-83 Volvo 7 series diesel from another forum member barkster1971. You would actually need the 1984+ type which is subtly different and not compatible, but this gives a general idea of what all was involved for the Volvo car system.
https://www.flickr.com/photos/186009...4/49214974317/
The Volvo cruise systems in that era were generally dealer-installed add on options, not from the factory, so this is how they were sold, as a complete set. The throttle spool stack and bracket on the left side of the picture is the piece that would be potentially useful for a Pinz but everything else I think would take a lot of work to adapt. The Volvo system takes a frequency signal from the Hall effect sensor in the rear differential that feeds the speedometer. Not sure how the speedo works on a Pinz but it may not have such a signal available. Then, the cruise control column switches, relay, control unit brain, electric vacuum pump controlled by the brain, pedal vacuum and electrical switches etc are all designed for the Volvo car... would take work and creativity to install in a Pinz. Not to say it couldn't be done.
Note that the Volvo cruise spools actually are well known for having problems with age and use. The bushings inside the spools and on the shaft suffer radial wear from engine vibration and eventually wear to the point that the spools themselves get damaged or no longer function correctly. Tom Bryant in Maine USA offers a service to rebuild the spools with new Delrin bushings. You might want to contact him for info on that or see if he has any sets available, if you choose to go this route for building a system. Sometimes the tin spring keepers on the bottom of the spools wear or fail also, or the d-profile on the shaft erodes from wear, and when these things happen there's no real way to fix it other than trying to find another complete set which are hen's teeth. There is a risk if you do find a used set that you may discover it's no good.
Below are some photos and a video I took of a cruise assembly set I sent to a member in Europe some years ago that show the function of the system and also show the failure mode of bushing wear, so you can get a better idea. Unfortunately this was the only spare set I had available.
https://photos.app.goo.gl/ddrjiDR7qwQtSfXU8
https://photos.app.goo.gl/bcx1rVU5yVEqwMKo9
That fellow (forum member "petercz") was apparently able to use these parts along with the electronic pieces salvaged from a completely different type of Volvo, a newer 850 series I believe, and ended up with a good functioning cruise system in a late 80s 760. So no doubt anything is possible with some clever thinking.
You could ask him for more details on his configuration.
The way I see it, if I were going about this, there would be two main paths to go down:
1) Try to get hands on an original Volvo D24T cruise control spool stack and vacuum bellows and associated brackets/hardware, use these parts (possibly after refurbishing the bushings etc) to handle the mechanical aspects, and then engineer and assemble an electronic control system, either from OEM junkyard vehicle parts (Volvo or VW/Audi also use similar type system) and/or partial pieces from an aftermarket kit, to operate the mechanical cruise components. This would perhaps be the most elegant, factory-looking solution I suppose, but, it would rely on the difficult to find and failure prone Volvo spool stack assembly.
2) Use a complete aftermarket system without attempting to incorporate the original style Volvo parts. Might be simpler and easier in the end. I think you could hook an auxiliary cable directly onto the main throttle lever, bypassing the spool you have, and it would work well. Probably need to fab some custom brackets etc but it doesn't seem like that would be outside your capabilities.
Here are some typical examples of the kinds of kits available from one of the big US sellers of this type of equipment, probably have similar systems available where you are.
https://www.summitracing.com/search/...e-control-kits
Hope that all helps, curious to hear how you decide to go.