80K miles is just about the right time for the belt to jump or break.
As time passes people tend to forget how things WERE and start thinking how things are now is as they have always been.
Back in The Day when a 2.3 reached 60k miles it was time to change the belt. The farther past 60k the engine went without changing the belt was akin to putting more bullets in the cylinder to play Russian Roulette. Eventually there will be a 100% probability of 'fail'.
Bogging could be caused by a malfunctioning accelerator pump (missing check ball), but if the engine doesn't crap out when the throttle is opened eventually fuel flow will catch up with air flow and hte should run like it's suppose to.
If the engine doesn't want to run above 30~40 mph under load (mixed terms?) I would wonder if the secondary is opening. Though an engine shouldn't need the secondaries to make it past 40.
Jumped timing ... those of us with V-8s who didn't gtet the plastic grar out of there in time know what jumped timing is like.
I've seen Fords (and other engines) with jumped timing. Some sound like they want to start, others will start but won't make it above an idle. Some will start and run, mayhaps even make it up the road,
some , not very well though.
Then there IS that cam issue .... Yeah, Ford did have a .... batch? ... of crappy cams back then ... Thanks for reminding me of this.
Yep, lobes sure could be burned off a '70s Ford cam. Why not? They were burned off in the '70s.
A humorous piece of Ford Folklore.