I am thinking it's a combination of parts causing this, even if they are all new.
The total lack of bushings in the car is a good start.
The trans from Passon has less then 200 on it, the drive shaft was installed with the trans and it's new as well, the rear diff is from Mancini's and it has I believe maybe 3000 miles on it.
I think its after the engine because it surrounds you when it happens but the steering wheel is fine, not completely but nut like the rest of the car.
Can trans do any vibing ? I will get the drive shaft rebalanced when I have it torn down for the bushings.
What is the likelihood of the rear diff causing this?
It's another clear cold day today so I think that I will take it out again and make some notes.
Traffic is light because of the holiday.