Shifter Mounting Block Out of Whack

Remove the plate, clamp it level in a machinist's vice on your drill press, and check the holes for true (turned off, plunge the appropriately sized drill into the holes- the one(s) that will not let the drill plunge is/are off. Drill to oversize and Helicoil the offending hole(s) back to original size. Now it will all be nice and square.