Vibration under load

[modtour99]

1967 dodge dart 273 automatic when you accelerate in passing gear the engine vibrates violently.Also slight vibration on acceleration above 55 mph.Removed insp plate don't see any broken parts.Thanks for any help

 

[hemi446]

I would try looking at your u-joints. It almost sound like one is tight on one side and when you put a load on it it just can't rotate so it's being forced around. Good Luck

 

[fishy68]

I'd also check the motor mounts and trans mount. if any of them are broken it could vibrate bad