2004R Transmission gear selector indicator issue

I have a GM 2004R transmission behind a 308 in my 49 coupe. I am changing the stock Hudson column gear selector indicator to show P R N D L.

The problem I am encountering is the shift lever, when all the way up, is in Park and the pointer is in the correct position. Then when I move the lever down the pointer moves quite a distance until in Reverse. Then it moves a normal distance into Neutral and again a normal distance into Drive. Once in drive the shift lever has reached its end of downward travel and cannot move any further into a low gear.

I'm not feeling much detent action when moving between the gears.

If this is a linkage adjustment issue could someone, please explain how to adjust it?

Or is it another issue? Any help much appreciated.