You should have done as much trouble shooting as possible before tearing it down. Sometimes a fuel pump can make a knock. If an object fell down into the engine and imbeded itself into the top of a piston, that would do it too.
Many times when a bearing spins, the piston can strike the cylinder head. There is only .030" clearance between the piston and cyl head.
Sometimes you can pull a plug wire one by one and determine which cyl is knocking, the knock will change.
Since you have it out. look at the front weight on the crank. sometimes the thrust bearing wears out and the crank can contact the block there.
Driving up a hill can cause the knock to go quiet with that problem, downhill will cause it to get louder.
If I had to guess, I'd start at the front and take off rod caps until I found it.
For some reason # 5 and 7 have more than their share of troubles. Could be the firing order.
Good luck, David
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