Pulled a hard hole shot today, everything went good except when I left of the throttle I had a really bad vibration, I stopped the car, the vibration is going with the engine at engine speed. Couldnt go much over 2500 rpm and its very very noticeable, I still have good oil pressure. And babies it home for about 5 miles. I'm guessing the new B&M flex plate cracked??? I just put it in. Convertor isn't slipping any, this is behind a 440 pushing 500-530 hp. What is the absolute best flex plate I can buy to put in this. I'm guessing / hoping that's the issue so I'm gonna order a new one anyhow if that's not ny problem I can use the extra flex plate anyhow. So guys what are your thoughts about this.

My first thoughts are I hoped you looked at your car closely before even posting this on the internet to find out what is wrong.

Then my second thought is I would look at my car closely before I ordered any parts for it.

Can't you just look to see if the flex plate cracked?

It sounds like your motor is out of balance, like a weight flew off of the torque converter or flex plate? Make sure the front of the motor is good( balancer, pulleys). Then I'd pull all 8 plugs and look at them. Hopefully it's not in the motor, but sounds like it.

if nothing obvious jumps out at you maybe do a quick compression check. DAMHIK