MrR - the longer rod [about 28-30"] on earlier trucks mates to a box with a shorter shaft on it, which might be your problem, if you have the correct 59 shift box .... might be easiest if you put the shift lever in place where the knuckle screws to the column to gauge length and just lop off the extra and re-notch as needed for the coupler ....
pic here, the correct one is
about 18", and note the difference in the knob and the lever shape at the knuckle
Bill
