Replaced blower last year when it started whining from a bad bearing, replaced with AC Delco that came with cage wheel to big, modified post to accept stock cage. Notices earlier in fall that it doesn't blow as hard as the original and the foot vents no longer blow as before.

Totally forgot to check this before dead winter as I haven't been driving the car, bought another two cars etc.
Is the actuated vent flap hung? My feet are FREEZING!

Is this an '84?

Yes, sorry. 84'. Bought blower from Amazon, said it was correct one. Just doesn't seem to blow as hard.
And of course the vent issue added in.

Same thing happened to me last winter, no hot air at the floor vents. Luckily it was one on the HVAC doors. Some of the foam/seal deteriorated and got wedged in there. Finally broke loose and foam dust blew out everywhere.