My 89 ford ranger

I have a 1989 ford ranger manual 5 speed. I just had the clutch replaced a few days ago but now the truck won’t go over 50 mph. The rpm reves high but it barley accelerates and when I push the gas pedal all the way down it acts like the engine is lugging out. I replaced the spark plugs and checked them the next day and they were soild black. Any help would be appreciated thanks in advance

If the engine RPM’s don’t match speed, then the clutch is slipping. Badly.

Take it back to whoever replaced the clutch.

Chances are that new clutch is now toast.

What are the RPMs at 50 MPH?

Actually, it sounds like something to do with the engine management systems got disconnected when the clutch was replaced, because what you are describing is an engine that’s running very rich, as if the cold start system was not shutting off as the engine warms up.

Smell like anything’s burning ? A slipping clutch gets hot fast & stinks with a burnt smell .

Dark plugs can be due to over-rich, but it can also be due to a weak spark.
Make sure all ground straps were properly re-connected after the clutch job.

The rpm reves high but it barley accelerates and when I push the gas pedal all the way down it acts like the engine is lugging out.

high rpm reving and “lugging out” are contradictory. Suggest to focus first on why the car doesn’t accelerate as fast as you expect when first starting out while at the same time the engine rpms are higher than expected. That’s definitely consistent w/a slipping clutch. And since this all happened immediately after a clutch replacement job , now’s a good time to find out of your shop’s warranty on their clutch job is going to be honored. It might be something simple, like some grease or oil has contaminated the clutch wearing surfaces.