74 dart vibration problem.

Well I had Cuda Mark look at it and he said the harmonic balancer looked ok and we really couldnt see the TC but noticed the dual exaust I had put on was pretty ridgid. The hangers have rubber washers but it's still very ridgid so I was told to put rubber hangers on them anyway. If that doesnt do it them I'm having this TC checked at a trans shop. Damm back keeps me from doing this stuff myself and this is getting real costly. I now have a 6500.00 ugly car that vibrates.