M11 to manual

You would have to get new injectors and possibly the entire valve train (would have to compare esn's). Then rewire engine fan control and engine brakes. Along with loosing cruise control. Then install a manual pump out of an L10.
Your money might be better spent on fixing your wiring issues.

 

I have one of those gutless turds too.
You will need new injectors ( much cheaper than the ones in the computer engine ), a different cam, and a different fuel pump which can be had off of any Cummins engine with the pt fuel system. Stay away from the stc system. You will need to set the foot feed up with a cable or linkage instead of the pot that’s under it now and as others have pointed out the fan (if it has an air clutch) will need some switches and wiring to work right as will the Jakes if it has them. And no more cruise control. It’s still going to be a turd but hopefully less troublesome except for cold weather starting.

 

The good old M A-lemon