Help! Small block 360 has a knocking sound

The engine was rebuilt prolly about 15-17 years ago, nowhere near fresh. However, I am the only person person to actually put some miles on the thing. I have only been driving it for about two years, and the engine has never made this sound until now.

Help an old guy out here. My hearing is terrible, plus your audio is too......no offense. lol Is it ONE knock or several? If it's several, it could be exactly what I am referring to.