Fuel Gauge and Temperature Gauge Dead

First thing, disconnect the battery.
Remove the speedo cable from the back of the cluster, take the screws out around the cluster and ease it out.
If you have the original amp meter in it those wire are pretty heavy and make it hard to get the cluster out.
Just ease it out where you can get to them and take them loose from the guage and then the next thing to remove from the cluster will be the main socket connector.
After that it's cake.
I have aftermarket manual temp and oil senders in my original guage locations, so I have to disconnect them both at the engine and pull the leads out through the firewall when I take mine out (so your lucky)

Anyway, I made a solid state VR for my original guages when they were still in there that you can have if it will help.
As you can see, I have played with my guages quite a bit.:D