Topic: Testing electrical system before installation of the engine. Safe?

[1967 eight barrel]

I wanted to test a few components before buttoning up the interior. All the electrical is in and complete, however the alternator harness is on the alternator on the engine and the ignition harness is as well.
As long as the battery is well grounded to the chassis, should all be well powering up to test dash and wiper functions, as well as lamps?

                                                                                                                         -Keith

[midlife]

I suppose you could test the system without an engine, but it is a bit incomplete.  Here's my guide for a trouble-free short check when installing wiring harnesses.

 First, always install electrical wiring with the battery disconnected.
 
Physically install the underdash harness with fuses.  Connect all underhood and taillight harnesses.
 
When ready to check out the harness, close all doors, turn off all lights, ignition key in the OFF position, accessories off, etc.  Make sure both battery connectors are disconnected.  Connect the positive battery cable to the starter solenoid.  Leave the negative terminal disconnected from the battery.  Then use a digital volt meter to measure the current draw across the battery.  Place one probe of the DVM on the negative battery cable terminal, and the other probe on the negative battery post.  Be sure that the DVM is set to amps, DC.  If there are no shorts in the wiring connections, the reading should be on the order of 30 milliamps or less.  Anything above 1 amp indicates some accessory is on; readings above 10 amps (may blow the fuse on the DVM) indicates a dead short.
 
If you have a short, disconnect all other wiring from the starter solenoid post where the battery connects and re-measure the current.  If current drops, the source is the underdash wiring harness or the harness from the starter solenoid to the firewall.  Reconnect the wiring to the starter post and then disconnect the underhood harness from the firewall and test again to isolate the source of the short. 
 
If the short is not in the underhood or underdash harness, the problem lies in the alternator or voltage regulator.  Disconnect each of these in turn to isolate the source.
 
If the short or high current comes from the underdash region, keep the battery negative side disconnected and remove one fuse at a time.  Measure the current as above.  If you now see low current, there is either a short or an item on that particular fuse circuit is on.  Turn off that item and continue checking.
 
Eventually, you’ll have low current readings with all fuses installed and all wiring connected.  This series of tests checks all of the battery directly powered systems.  To check the Accessory systems, now repeat all of the tests above with the ignition key in the ACC position.  The current with the key in the ACC position may be up to 1 amp or so.  When all of the tests are done and no anomalous current it noted, at that time, and only at that time is it safe to connect the negative battery cable to the battery.
 

[1967 eight barrel]

Randy,
Thank you for replying. The only wiring not installed is the alternator harness where it plugs in at the solenoid,the cable from the solenoid to the starter and the turn signal/column. All harnesses are new except the under dash unit, which I simply wanted to make sure the wiper motor was in the parked position as well the instrument cluster lighting, as I wanted to confirm the voltage regulator on the custer was good.

                                                                                                                         -Keith

[midlife]

I think you'll be good, but follow my instructions before hooking up the battery.  You won't be able to check out brake lights and turn signal lights without the turn signal switch installed, though.