I have knoticed that if im reving my engine in park or nutral once i let off the gas and the engine slows i will here a thud sound what could this be.

Possibly a motor mount or torque arm??

how much are torque arms

phantom-

Open your hood and take a peak atthe engine as you gun it. What do you see? Does one side of the engine (probably the driver'* side) lift up?

You might even have a beautiful blonde assistant in a bikini sit behind the driver'* seat, push as hard as she can on the brake pedal through this entire procedure, start the engine, put it in drive, step on the gas for a couple seconds while you have the hood up and watch the motor like compyelc4 said.
When she does this, if the motor acts like it'* trying to jump out of the car, you've got a broken motor mount, or one of those torque arms (is that the right name?) that'* worn or broken.

whel it only dose it when it is in park or nutral Tommorow after school i will turn on the car and open the hood then rev it by opening the TB.

Since my wreck the hood has shook makeing the handeling at high speeds not as good Is there some thing i can do to rais the hood rests or fix this .