Help identify if hurst shifter is correct one

As stated earlier, the mechanism will work on your Dart. IIRC, the A-body versions of the transmission had a shorter tailshaft until 1974 or 75. It is probable that the mounting kit for the A-body version is different from the B/E versions of the 833. The primary difference is going to be the length of the shift rods connecting the tabs on the shift mechanism to the levers on the side of the transmission.