For anyone wanting to do this swap correctly, it is a bit more complicated than it first appears.
I did this conversion for a 1970 FJ40 about three years ago.
Several things to be aware of: If installing on any FJ40/43/45 that is pre-1972
50A Amp Meter
The 50A amp meter in these clusters barely works in the FJ40 they were designed for. Ask anyone who owns one. They will tell you the meter barely moves when in use and that is with a 50 amp alternator! If you hook it up to a 30 amp alternator (using the sub-harness described below), the 50A Amp Meter probably won't move at all. (There is a LONG thread here on MUD about getting the meter to work correctly. I would suggest you read it.
Clusters, Gauges, Speedo & Odo meters The Amp Meter stuff starts at Post #74. )
However if you insist on hooking it up you are going to have to have to make a couple of major wiring changes to the main cowl harness.
First you will need to replace the main charge wire. On pre-72 FJ40's this wire runs from the Amp Meter to the starter B+ stud. This 10ga white wire will need to be removed from the harness and replaced with a longer wire that terminates out to near the battery. Then you will need to install a 78-82 fusible link assembly on the end of that wire. Next you will need to install a later model Amp Meter sub-harness with fuses. This runs from the fusible link, back to the Amp Meter, and contains two 5 amp fuses to protect the Amp Meter. There it terminates in a three terminal connector that plugs into the back of the Gauge Cluster. I built this harness from scratch.
Here is a semi correct/incomplete drawing of this sub-harness... Seems I did not take pics of the completed one...
View attachment 2138735
Harness interface
Next you will need a harness interface sub-harness to mate the new gauge cluster to the old gauge cluster. This is a pretty simple harness. The one I made included the ability to have both the older dash turn indicators AND the new gauge cluster turn indicators work at the same time. Here is a pic of this harness: (Note: I made this from a salvaged round gauge cluster connector. These connectors are now available thanks to some hard work by Matt!) Again the sub-harness shown was for a 1970 FJ40. The harness will vary depending on what year you have. Especially the 1973 version!
View attachment 2138730
The two 4 pin male connectors plug into the two 4 pin female connectors on the main cowl harness for the old gauge cluster. The two pin connector mates to a 2 pin female connector. You will have to run two wires from the gauge cluster plug area to the turn signal switch area in order to pick up the dash light turn signals. Again this part is optional.
Sensors
Now you have to swap out the fuel tank sending unit, the water temp sensor, and the oil pressure sending unit for ones that match the new gauge cluster. Failure to do this will result in gauges not working.
Final thought: you also have to deal with the Speedometer/odometer reading in Kilometers instead of MPH/Miles...