Metallic whirring at higher RPM?

[Chained_360]

So my 1968 Barracuda has recently developed an issue that occurs at higher engine speed (nothing crazy, just high enough to be going ~45 MPH). It sounds like it's at the back of the engine or closer to the firewall, and sounds like very light metal-on-metal contact, like something spinning without sufficient lubrication. However, at the same engine speed, I have 60 lbs of oil pressure. It first made the noise at low RPM (just above idle), and now does it at higher RPM. It also occurs whether the car is in or out of gear (904 3-speed). What's up with that?

 

[Mr.FT]

If it makes the noise only when moving I would check the speedo cable as a starting point.

 

[Dartswinger70]

Whirring? sounds like a possible bearing noise.

 

[Locomotion]

Flexplate cracked?

 

[MOPARJ]

Any video of noise? Is there any roughness of the engine associated with the noise?

 

[MOPAROFFICIAL]

Could be speedo cable, intermediate shaft bushing failed, or front pump on trans...since we're just guessing.
Cracked Flex plate sounds like a clacking and or rattle.
Look at the torque converter check plate and see if its loose or touching moving parts like the flex plate or converter.

 

[AJ/FormS]

Look at the torque converter check plate and see if its loose or touching moving parts like the flex plate or converter.

I like this one.
You can also see crank end-play by prying the crank back and forth at the damper. Sometimes I have seen it on a running engine with the damper bouncing back and forth,keeping time to the noise.

 

[Alaskan_TA]

Check to see if any of the flex plate bolts are loose or have too tall of a head also. If one is loose or not the right style, it can hit the webbing cast in the back of the block.

 

[Chained_360]

Well, I think I may have found the issue. I'm currently pulling the starter out and the crown piece of the aluminum casting is broken off, which may explain why the sound goes away if I shut the engine off and turn it back on.