sounds like a top end tap. check the flexplate takes 5 seconds, just get under the car and look at it.

 

Yea I removed the valve covers and didn't find anything

 

Valve train noises are at half the RPM of the engine (crankshaft). Flexplate noises are at engine RPM.
A agree with DietCoke that it sounds like valvetrain - you are reving to maybe 1500 rpm and the noise occurs about 12 time per second.
Flexplate noise would occur at 25 times per second at 1500 rpm.
I suspect you won't even hear it under the car.

 

It's actually pretty loud under the car and when I used a stethoscope it seemed to be coming from the bellhousin

 

A stethoscope can certainly help chase down noises.
I don't have any experience with broken flexplates and will therefore drop out of this discussion.