Cool. Two cars same year. '74 can be some fun figure out. But at least its a similar puzzle on both. Could be looking at a heavy duty option. Could be looking at a seat belt buzzer or interlock that was removed. Or?
Start a thread about your cars.
State what options each one came with, and show some photos of the firewall and the column connector. Be clear about which car as they could have been optioned differently. Options such as rear defrost effect wiring.
For example this is a big clue.
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