Hi. Thanks for using JA! I will try and help you out.
Are you saying that you want to eliminate the governor on the engine and replace it with something else?
I see. I have not seen that before. To be honest not sure how it works.
If you can get some good info on it and they have done them before, it may work fine.
I have heard that folks have installed a pump on 3116 engines before but I have not seen it before or how well the pumps did. Sorry.
I would like to think that if a pump was installed between the tank and first filter, it should work fine. I agree with you, not sure if I would want to bypass the pump on the governor.
I would not steal power fromt he shutoff solenoid. This may turn into a problem later on and cause the engine to shut down.
The plastic lines are quick connectors made by GMC. I believe they are 1/2 inch size lines.
I would get the 12 volts straight from the battery or fuse box. I would make sure there is a fuse in the circuit as well. I do not like tapping into other 12 volts circuits because that can cause problems sometimes. If you tap into another circuit, you could cause an overload on that circuit and then blow a fuse.
You should be able to find a good union at a hardware store that will connect the lines if they are different. Most places sell many different size adapters and unions.