Some light knocking coming from the motor under acceleration, so went and checked the oil and wasn't even showing on the dipstick! Added two quarts, and she is running happily again. Haven't ever owned a truck or car that has lost much oil, so this was a lesson to me to check the '82 often. Good news is she seemed to be (somehow) running great 2 quarts low on oil and even better now that she's topped off

 

You might want to find out why it's loosing oil. Might be a bigger problem. Knocking is not a good noise to hear on any motor.

 

​​​​​Got any oil leaks? Blue smoke on startup maybe?

That oil's going somewhere, so if you don't check the level every few hundred miles out of habit, best to track down the source and fix it.

Could be as simple as valve cover gasket, half moons or distributor hold-down bolt.

 

Im almost certain its internal..Get some pretty heavy smoke on startup when the choke is engaged and its been sitting overnight, but it goes away in a couple minutes once warmed up.. Engine exterior is dry.