1988 bronco11 with 2.9l loud knocking

blowed a head`gasket.been sitting for two years.changed it today.started it up and a loud knocking from the left side.let it run for a hour so oil could get to all parts.still knocking.so i started pulling plugs to see whick one was knocking.when i pulled the one that is knocking,it stop knocking.now it runs fine with that spark wire pulled.can any one give me a idea what the knock could be.

Sounds like who ever had it when the head gasket was bad spun a rod bearing.