1990 Mustang GT 5.0 Problem

The car shakes like a wash machine off balanced I replaced the harmonic balancer because the rubber was coming out of the old one. It's a 5 speed even sitting still and reviving the engine you can feel it in the stick in gear or out of gear i know a 50oz flywheel and 50oz harmonic balancer goes on it but the guy I bought it off of done alot of work on it it has a new 302 crate engine with gt-40 heads could it new a 0 balanced harmonic balancer and flywheel or even a 28oz. Help I've had 3 people go throgh the engine so far including myself and we are still scratching are heads.Any advice at all would mean the world to me.      

this may be a dumb question but are you shure all the motor & transmission mounts are properly installed??? sounds like something isnt porperly alined  

I have the exact same problem. replaced the motor mounts and transmission mount with brand new eurothane ones and it didnt help. replaced stock balancer with a fluid one didn't help, replaced fuild dampener with a new stock one, still nothing. Soon as I get some spare time its going up on the lift and the tranny is coming out of it. I planned on replacing the tranny and would be a good time to check out the clutch alignment, pilot bearing, input shaft, ect. Let me know if you find the problem and I will do the same. It really doesnt effect the way the car runs in my case but it's just kind of unsettling. My friend suggested the motor was internally out of balance. I could be wrong but if something inside the engine was out of balance it would seem to me it would come apart or something.  

when my balancer came apart like that i was told to check and make sure the crank doesn't have a lot of play in it.if it does you need new bearings.