grid heater power cable attachment at grid heater

I am trying to remove the power cables from the grid heater. The nuts attaching the power cables to the grid heater turn along with the stud / bolt when I attempt to loosen them. The stud / bolt isn't affixed to anything so somehow the other end needs to be held. I'm not sure how that is to be done. An impact wrench may get me past this or it may cause damage, I'm not sure.

What am I missing here?

Here are a few photos of the grid heater.

https://share.icloud.com/photos/052cv6ZFX0tFGt0G965RJqR4Q

Thank you for any help.

 

To me, it looks like a cover plug over the other end of fastener. Like the type of welch plug in a carburetor.

 

You could try making a slit/detent on the top of the stud just large enough to get a flat blade in the grove to hold it while you turn. Like the hexes and allen heads on shock rods. Make sure all power is disconnected of course.

 

Thank you for your help, guys. Both are helpful ideas.

 

Just my opinion. I would remove that GH ASAP. Replace with a new GH or a GH delete plate. Sounds like the stud & nut on the back side has arced enough to loosen things up quite a bit. If that portion of the stud / nut fall off it will be good bye cylinder #6 and the engine.

 

I hadn't thought of that, Joe. Thank you. It won't be reassembled that way. I will have to do something with the grid heater and connections.