Recent knocking from engine head cover on original 2F motor

[Rue]

Hey everyone, so I have a 82' FJ60 with original 2F engine 4 speed. A couple of weeks ago I was driving home from work when while in gear it shut off hard jerking the engine, wouldn't start, the engine would barely even turn. Had to tow it home. I checked the plugs and plug wires and distributor cap. All were good but changed the spark plugs anyways since they were due, was low on motor oil also. It turned on finally but now there is a knocking noise coming from the top of engine cylinder head cover, this knock wasn't there before this incident. At idle its fine, but once I rev the engine up to around 2K it starts knocking. Any thoughts and/or advice on what to look for or check?

Many thanks in advance!

 

[60 toy ota]

when you say the oil was low, how low do you mean?

 

[tag3]

Was there oil on the pass. side of the engine?

 

[Rue]

It was 3 qrts low. No I didn't see any abnormal amount of oil.