I have a noise that can best be described as a muffled exhuast leak like sound. It goes up and down with the rpms in speed and volume. When the clutch is depressed it still makes the noise but it is not nearly as loud. It sounds like a deep vibration. Rattles my teeth at 70mph. Any clues?
James

 

bump, oil pressure is okay, idles normally, just sounds bad running up the rpm