71 Dart 727 w/suregrip having weird issue

Well i double checked the fluid level and condition, checked out good. I did finally get it up on a lift today and found one trans mount bolt loose and the other missing. I fixed that and it did get a bit better but not totally. A friend of mine who tinkers with race cars had me hold the brakes and give it gas and see if it gets worse and it acts normal, nothing weird happens. Shifts fine, drives fine...just weird vibrations. Also feel them slightly while coasting from around 40-50 mph. I have been told that exhaust vibrations can confuse people and sound like drive train problems? One more thing I did find was something I hadn't thought of before......my exhaust hits my driver side torsion bar, my passenger side rear frame rail, and my passenger rear spring shackle bolt. Could all of this weird pulsating while stopped be these things vibrating together?
Ummmmmm, did someone mention that in post #2??? Hope you get it sorted out...