well... 71 diagram for back of rallye cluster
( sorry pic is tiny and hard to read, but still can be read on a close up )
.... get it to the red side will work too and the load the clock sucks out is minimal... just not the correct side
On standard cluster, and on the rest of clusters kind where the clock is not sourced with a jumper wire from ammeter, the source is from fuse box, which is powered from black side of ammeter.
The red side just must get the wire straight from the battery on all cars, nothing more, nothing else.
With an ammeter on car NOTHING must be sourced between ammeter and battery, and NOTHING must be sourced from batt post either. The ammeter must be read JUST the battery status, so anything sourced from this side of the line will disturb the load reading status and even overload the system.
Once again, the clock is something that could be even obvioused, because it means allmost nothing to the system, but, just in case and for correctness.