1969 340 is down

Long story short I acquired a 69 340 swinger that has a rebuilt engine. Everything was fine until I hear a noise similar to a flywheel/ring gear hitting the inspection cover. Noise lasted about 5 seconds give or take. After the initial noise stopped I realized lost of power. My destination was 3/4 mile away so I proceeded. After removing the spark plugs and doing a compression test one cylinder was zero, #3 I believe (second from the front, pass side). Removed the value covers and low and behold the rockers appear to be out of place. (See pictures). Anyway I'm pulling the engine and going from there. Just wondering what the membership has to advise. Thanks in advance.

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