I started hearing a rattling from my engine last night. I thought mabye it was a loose rocker so I proceeded to take the valve covers off and check but when i was taking off the spark plug wires on of the wires came out of the boot rather easy. I just rebuilt the motor to a 383 and got about 500 easy miles on it. So i have been taking the spark plug wires on and off rather frequently checking stuff. After the wire fell apart I took all the wires off and cranked the engine and there was to knocking anymore. Also when the car was running the rattling would not increase with RPM's. It mainly did it at low RPM's. My question is could a loose spark plug wire cause the engine to knock. I did notice that it was running a really low RPM when at Idle and shaking alot.

It's possible.

Get all the wires and plugs up to snuff and see if it quiets down.

well i got the new spark plug wires on. Still rattling sound coming from the front of the engine. It started to whistle a little to. Could these be a spun bearing. I only have about 500 miles on the engine. I have good oil pressure. The only other thing i can think it would be is the timing chain hitting the cover. I didnt put a new one on when i rebuilt it. Stupid move i guess. Whats the easiest way to know if its a bearing or timing chain?