First thanks everyone for your thoughts and suggestions.

I too have been trying to figure out what I might have changed to cause the vibration. There have been no mechanical changes or additions to the car from the pre-vibration state. After first noticing the vibration, the vibration has remained the same, although there are not a lot of miles or run time since then. Shortly before noticing the vibration I did reset the points and adjust the timing. I don't remember if it was immediately before or not. I checked the dwell and timing again yesterday and they were spot on. I did not pull the distributor cap to see if something might be going on inside the cap. I don't hear any strange noises. Hard for me to believe that this is a possible source, but will check.

When my alignment/suspension mechanic inspected the car, he looked closely for loose bolts and anything that could be touching any part of the body of the car. He has more than 50 years experience with brake, suspension, alignment and has worked on many Mopars back when they were regularly on the road. Before looking under the car, he drove it and after the drive he told me that he would find something under the car that was causing the problem. The vibration in the steering wheel, made him think it was something loose or hitting something under the car. He found nothing and said that it was either an engine or transmission problem in his opinion. I do need to checkout the motor mounts a bit more closely. They are new, but Chinese mfg. They look OK, but may actually remove them to inspect.

I did spend some time looking at the TC. The bolts to the flexplate are tight. The flexplate appears to be tight to the crank. The bolts to the crank appear OK but really can't see a lot. I did not see any cracks in the flexplate. I did not watch the flexplate/TC while bumping the engine over to look for any looseness. Will put that on the to do list. I also did not watch the converter with the engine running to see if there was anything obviously not running true. I have a 2 post lift, so can do that. The engine is externally balanced and the TC is a stock 10 3/4" neutral balance unit. I looked to see if there may have been a balance weight on the TC that came loose, but did not see anything. I have the stock shields on the bottom side of the bell that would keep any part that came loose from getting out. I did not find any loose parts in there when I removed the shields. I have not checked the engine to trans bolts, so that will be on my to do list.

I have stock manifolds on the car, but the heat riser butterfly in the right side manifold was removed.

I too was beginning to suspect the converter. Assuming I don't find anything else, probably will pull the trans back, inspect the flex plate thoroughly and swap out the converter.

It was suggested to me that perhaps a chunk of mallory metal put in the crank during balancing might have dislodged. I don't know if there is any mallory in the crank or not, my receipt for the engine work just says balance crank assembly. The new pistons I put in during the rebuild are about 60 grams lighter that the old ones, so I suspect when it was balanced they had to remove metal from the crank. Intend to get back in touch with the shop that did the balancing and see if they have any recollection, but it has been 3 years.

I edited the video I made with my iPhone that shows the steering wheel vibration to a few MB with the intent of posting it. However, the file format is not one of the allowed formats, so don't know how to show you what I'm dealing with. So, I added a couple of pics to give you an idea of what I'm working on.

Thanks again for the ideas and suggestions. If you have additional thoughts I'd love to hear them. I'll try to keep this post up to date.

R/ John