Anybody seen this before?

If you unplug the plug at the seatbelt buckle itself on a 1974, the interlock system is disabled, and no other I'll effects like losing lights, etc.

If you locate 2 wires under the hood running to that interlock thing, and hook them together, it 100% bypasses the interlock, and you can even pull the under dash blue interlock box out of the car. (I think the wires are yellow, to brown/yellow) but search on here if you want to confirm.)