I don't have any installation pictures but wiring should be straight forward. Run the ignition 12V, and illumination 12V wire to the fuse block. Crimp on 1/4" female terminals to those wire ends and then plug the ignition 12V wire into the center of the box marked IGN and the illumination wire to LPS. Crimp a ring terminal on the tach's ground wire and put it under a bolt under the dash.
The signal wire (tach wire) needs to be either run through the firewall to the negative side of the coil or to the tach terminal on the HEI. Use crimped on terminals here also. If you car had a factory tach then if the wire is still hooked up under the hood and run through the firewall bulkhead connector you may be able to tap into it under the dash but it might be easier to shoot a new wire out to the coil or HEI.
If you run a wire through the firewall try and use an existing hole with a grommet around the wire to prevent or reduce the chances of a short. If this wire shorts out the tach will quit working which is no big deal but it could keep the engine from running.
Your other two terminals in the fuse block are fuse protected but if your tach needs an inline fuse, add that also.
Jim