93 Ford Escort Wagon loses power when trying to accelerate from 60+mph

[abates]

This is a manual, it is possible the clutch could be slipping, unfortunately though I can’t say for sure whether or not the rpms are increasing, Ford neglected to include a tach in this model… How just going by the vibration feedback I get through the shift nob the rpms are increasing very much if any, the vibration stays pretty steady.