best shifter

If you have no modifications done you probably have a CompPlus.

The Super Shifter is more than just a handle swap.... The rods and mechanism are not the same and it will not fit without modification.

Sorry to disagree, but I have a Super Shifter (I know this for a fact) in my '73 340 Duster, and absolutely no modifications were done to install it. The newer Super Shifters may be different, but mine is 33 years old.