Uh-Oh, Noise inside my 1966 425

Hey All, just started it up after a long 3 month sleep and all of a sudden a noise arose. It sounds like a baseball card in the spokes of a bicycle. Kinda weird sounding to me. Never heard of a noise like this. Anyone have any ideas as to what it could be? Thanks for reading this.

 

Was quiet at first, then about 30 seconds later the noise started. Took the belts off to eliminate all driven accessories. Noise sounds like from center of engine. Like baseball card in spokes. Faster sounding with rmp's.

 

I would check on the flexpate.

 

Ok, Sunday afternoon it started right up no problems. No noises, no hesitation, nothing. As if nothing was ever wrong. I am at a loss....

 

Could it have been a carbon knock? Cannot remember what they sounded like, but years ago remember having them on a high compression 70 455.

 

455 Oldsmobiles - which have a totally different 455 - would do that too.

 

My vote is lifter..my hydraulics on the 65 would go in and out like that with 75k on them