I mean, the state is what, 40% Democratic now? I'd bet it was at least 50% then. Carter destroyed Ford in AR, which is culturally similar to southeastern OK. Plus, Carter's Christianity should had gone over well with in the Oklahoma City area, no? Was Ford really that great a Republican for the state?
what's odd is that it was the large counties (Oklahoma and Tulsa) that did him in. He did pretty well in the rural areas.
Tulsa especially has been a GOP stronghold for decades due to the role of fossil fuels in the area.