I've been listening to the vid you posted but am having trouble hearing every thing.
You could remove all the tin work you can including the hood, but leave on the muffler. As much as I don't like someone to run a knocking engine, start it up an see if the knock is still there.
I f you have to do engine work, knowing what can show up on a tear down figure on a complete rebuild. Sorry but with what has happen to me in the past I don't cheap on the power plant. I don't spend more than I have to, but skimp or cheepo on a rebuild don't cut it. I had to fix too much cheepo's other people did. I wont do that on my I rebuilds.
Just remember
1.If you don't do it right the first time, you may get a chance to do it again.
2.Don't use sealer on gaskets when you reassemble the engine.
3.Take your time don't rush the repair, just do it right.
4.When in doubt get help by professional or information from people in the know.
I am rebuilding a 1450 right now. I have more in it than I wanted but it will be done right It cost more if I cheep on it and would have to do this again.
I hope I helped.