Post a photo!!!
I didn't realize this was a 74. You don't still have the seat belt interlock box do ya? This has a reset button on a horn relay looking box under the hood. The starter relay "start" wire goes through that. If you have it, you need to jumper the two yellows together
This thing here.........
View attachment 1715052239
So far as your dissection, I'd be making sure that the relay is actually what is failing. Hook the two spade connectors to a battery........does it pull in? If not the coil is bad. If so, inspect the contacts. If they look fairly clean, there's likely nothing at all wrong with the relay