After chasing a bad vibration in the driveline for the past few weeks, I have finally come to terms with the very distinct possibility that the torque convertor is the culprit and will need to be swapped back out. So, does anyone have any tips that may be helpful. I don't want to pull the engine and transmission if not necessary and I know some of you guys have done this swap on a pretty regular basis. Any help would be greatly appreciated. 73 Dart Sport 340, 727, TTI headers. Thanks in advance!

Did you put a converter in with out weights for a cast crank 340? You need aconverter with cast crank external balance 340 or a flex plate for the same to eliminate the need for the weighted converter. Replacing the converter will not help unless you do one of the above and you may not need a converter if what I stated is the case.

YOU CAN WELD A WEIGHT ON WITH IT IN CAR,I ALWAYS DETERMINE AS TO WHERE THE LOCATION OF THE WEIGHT SHOULD BE IN RELATIONS TO FLEXPLATE POSITION, I THEN SAND/GRIND THE SPOT DOWN TO METAL FOR GOOD GROUND AND WELD IT[TACK WELD A COUPLE SPOTS]OR TAKE IT TO MUFFLER SHOP AND DO IT UP IN AIR AND HAVE IT DONE....MUST BE IN RIGHT SPOT AND DONT GET CARRIED AWAY WITH WELDING.........

Cast crank as you already stated, neutral TCI convertor and a B&M 10235 flexplate. I had a TA in it and when I went back to the TCI, the vibration really showed up. I'm not saying it wasn't there with the TA,( I can't really remember) but it really bothers me with the TCI in there. The only other thing that has changed was new inserts in the motor mounts when the engine was put back in.

It seems that the driveshaft isn't running straight down the center of the tunnel under the car. So, I investigated further and found that the tranny mount isn't squared up either. Apparently the engine is setting a little crooked in the mounts. A tube from the #5 header looks like it is hitting the steering box and not letting the engine sit in the mounts square. Does this sound like a reasonable cause for a vibration?

The vibration is definately in the transmission. It will vibrate in park and gets progressively worse above 2000 rpms. When laying under the car with it running, I have no doubt it's in the transmission. I just have to figure out what )convertor?) and why the driveshaft isn't running straight down the tunnel. (is that common?)

Common, I'm not sure but there are alot of vehicles out there with a driveshaft not running straight down the car. Some front driveshafts on Jeeps are like that and we are talking about a 3' shaft.

Either way you can concentrate your efforts between the harmonic balancer and the torque convertor.

I always use a little spray paint to mark the tc and flex plate

saves time bolting it up

if the mount is slide over and rubber is mushy

it could let it vibrate,header tube on the frame is not good

I would check the rubber engine mounts along with the tranny mount and try again

Thanks guys! I'm gonna swap out the PS box with a manual and see it the additional clearance allows the engine to sit straight and probably put the TA convertor back in. So, does the transmission have to come completely out to swap the convertor? I don't think there is a real possibility of moving it back enough to get it out and back in.