Rick you are saying the shifter won't go over, [as into the "H" pattern] or it will not actually shift? If it is the shifter will not slide over, I am betting your shifter needs a rebuild, this is pretty common with an brands of well used shifters, I've had a couple myself and for a long while, stick cars were pretty rare in my price range when I wanted one, so that means I have only had a few stick cars. If the tranny will not shift it could still be the same thing as the sloppy shifters ends up putting the tranny [almost] into two gears at once. Just somethings to check out, at least the checks are free of expenditure, except time.
Harry
I'm not a hoarder I'm a preservationist 78 Monza Spyder (~Soon(ish +/- I guess) To Be 2+2 with Spoilers)