Might just be the way the camera picks up the sound....... but the valve train seems noisy.

Did you check v/p clearance on this motor?

Exhaust sounds extra quiet.

I wouldn’t expect that can to be particularly muffler friendly(or a very good match for the stock 301 manifold)....... especially quiet mufflers.

I think you need to leak it down.

I also agree you should borrow a non-dial back timing light.