I have a 57 Tbird with a 312/Fordomatic.

I have an engine vibration that is bad at around 1300 rpm. Anything below or above this rpm is significantly less but still there. It is not driveline rated as it does it even in park or neutral. The car idles very smooth and quiet and runs nicely. I have noticed it is more noticeable now after replacing the rear motor mount.



Thanks