want to tighten up a sloppy side shifter. have new front bushings, cone screws and side shifter linkage installed. but still have a good 10" of play between gears when shifting. guessing the problem lies in the actual shifter assembly. whats the fix?

If a new firewall two coupler rear crown glued in and ball cup bushing, both set screws are tight, roll pin on transmission shift lever is tight, plastic flat washers are installed, the rear bar is not bent out of character and the front set bolt is tight and the shift lever is not rubbing on a broken clutch tube, then check the rear shift bar to make sure that the spot welds are not broken where it is joined together
There should be no reason to suffer sloppy shifter in a late model car. We have never seen shift base bushings broken although include them in our large shift busing kit.