I recently done the ST-300 to M-21 swap and my last piece of the puzzle is the shifter. I have a brand new Muncie aftermarket (bolts to the crossmember) shifter that can be used, but am I wasting my time? Should I get rid of it and go to the Hurst Comp Plus? No worn parts here...everything will be new.

Thanks in advance!

Unless you plan on regular racing, I say go with what you have.
In my 45 years with our '67 I have not had one issue with the Muncie in it.
Cal

Muncie shifters were factory in many muscle cars, including my father's 69 Chevelle SS. Not one problem with it. Only thing I have heard about them, but it the same with most manual shifters, bushing wear out and need to be replaced/shifter rebuilt. I say use it, drive it and have fun.