My 85 impala battery is fully charged, alternator is working and starter is brand new but it wont catch to turn over. what else could b the problem

You may have to install some starter shims.

Do you mean the starter is turning when you turn the key but the stater is not engaging the flywheel to turn over the engine? If that is the problem, see answer above. If the starter is not turning at all, make sure all the wiring is connected from the battery to the starter. Are there any lose or non connected wires?

All wires are connected and yes the starter is turning but not engaging

Than it is a shim issue and the ones that put in the starter need to fix it at no cost.