the bell housing was flush against the block I did not have to use the bolts to get it flush, and I am confident that the torque convertor did not slip out of its seat.
If you have the right bolts, then I would think it is a problem with the flex plate not the cover plate. Some plates have a different off-set to the crank (dished) and are for specific applications. Make sure all your parts fit the same application.
Paul all of the parts are from a lincoln mark vii, mine is an 88, the one the transmission is from an 87.